Mark 10:46 is one central piece of evidence showing that canonical Mark derives from Secret Mark, as it explains the pointless mention of a visit to Jericho (describing Jesus' entering and leaving Jericho without telling what happened there) and the change in subject from singular to plural:
"And they came into Jericho. And the sister of the youth whom Jesus loved and his mother and Salome were there, but Jesus did not receive them. And as he left Jericho with his disciples and a large crowd..." (Secret Mark 10:46)
"And they came into Jericho. And as he left Jericho with his disciples and a large crowd..." (Mark 10:46)
But there are many other things that Secret Mark explains. There is evidence that the original version of Mark underwent revision before the canonical edition was disseminated: the common omissions of passages and phrases from Mark in Luke and Matthew which may be viewed as later additions to the text (cf. Mark 2:27-28; 4:26-29; 10:21, 23, 24; 12:29-31; 14:51-52), divergences in Mark from the wording in Luke and Matthew which may be viewed as instances where Luke and Matthew preserve the original form of the text (cf. "To you is given to know the mysteries of the kingdom of heaven/God," Matthew 13:11; Luke 8:10; "To you is given the mystery of the kingdom of God," Mark 4:11), and there is special vocabulary in Mark which is absent in parallel passages in Matthew and Luke (especially didakhe kaine "new teaching" and thambsthai/ekthambeisthai "to be amazed"). Most strikingly, the terms "to teach" and "teaching" (didakhe) occur frequently in Mark where they are absent in parallel passages in Matthew and Luke (cf. Mark 1:27; 2:13; 4:1-2; 6:30, 34; 8:31; 9:31; 10:1; 11:17; 12:35-38, etc.) All this suggests that Mark was redacted after its use by Luke and Matthew.
Several of the common omissions in Matthew and Luke are directly related to Secret Mark. The rich youth that Jesus resurrects in Secret Mark 10, who forms a direct parallel with the Lazarus of John 11, recalls the rich youth in Mark 10:17-22 and according to Mark 10:21 Jesus "looked at him and loved him (emblepsas auto egapesen auton)." This passage is omitted in the parallel pericopes of Matthew 19:16-22 and Luke 18:18-25. But this phrase forms a direct parallel with Secret Mark 10:34:4, which says "the youth looked at him and loved him (emblepsas auto egapesen auton)." As pointed out in the last paragraph, Matthew 13:11 and Luke 8:10 lack the wording of Mark 4:11 where the word musterion "mystery" occurs in the singular: "To you is given the mystery [musterion] of the kingdom of God." This is paralleled again in Secret Mark 10:34:6 which remarks that "Jesus taught him the mystery [musterion] of the kingdom of God." But the most enigmatic verse in Mark also has a parallel in Secret Mark. At the scene of Jesus' arrest, Mark 14:51-52 mentions a rather bizarre happening: "And a young man followed him dressed in a linen cloth over his naked body (peribeblemenos sindona epi gumnou); and they seized him, but he left the linen cloth and ran away naked." This story is absent in the parallel accounts in Matthew 26:47-56 and Luke 22:47-54. But the resurrected youth in Secret Mark was described in exactly the same manner: "After six days Jesus told him what to do and in the evening the youth came to him, dressed in a linen cloth over his naked body (peribeblemenos sindona epi gumnou)" (Secret Mark 10:34:5). The simplest explanation of the overall pattern is that the first edition of Mark lacked the characteristic language (e.g. the frequent use of didakhe), the comment about Jesus loving the young man in the rich youth story (Mark 10:17-22), the resurrection story (Secret Mark 10:34:2-6), the story about Jesus on his way to Jerusalem possibly accompanied with the rich youth (cf. Secret Mark 10:46), and the story of the youth fleeing the scene at Jesus' arrest (Mark 14:51-52), and it was this version that Matthew and Luke used. Then the gospel was edited and expanded with these pericopes added, producing Secret Mark. Finally, several of these additions were removed (leaving intact such episodes as the naked youth at the arrest scene), producing our canonical Mark in the NT. Changing "mysteries" from plural to singular in Mark 4:11 would have also logically been from the same hand that inserted the resurrection story that referred to the "mystery of the kingdom of God".
This emphasis in Secret Mark on the resurrected youth might also relate to the Empty Tomb story in Mark. Mark 16:5 says that when Mary Magdalene, Mary mother of James, and Salome "entered the tomb, they saw a young man sitting on the right side, dressed in a white robe; and they were amazed (exethambethesan)." This reference is simply to a young man in a white robe and nothing more, while Gospel of Peter 13:55 refers to "a young man, comely and clothed with a brightly shining robe," Luke 24:4 refers to "men in dazzling apparel," and Matthew 28:2-3 refers to "an angel of the Lord ... [with] an appearance like lightning and raiment white as snow." These texts seem to attest an evolution of the presence of a young man into an angelophany. One connection with Secret Mark is the figure of the young man, another is the presence of this young man inside a tomb in a resurrection narrative. A third is the use of the verb exethambethesan "astonished," which occurs only in Mark and is absent in parallel passages in Matthew and Luke (cf. Mark 9:15; 10:24; 10:32). One possibility is that the redactor of Secret Mark wanted to identify this announcer of the Resurrection with the youth that Jesus had himself resurrected.
When the common omissions and departures from the text of Mark in Matthew and Luke are viewed as the result of the redaction of Secret Mark, an amazingly coherent structure appears in the gospel which reveals the purpose behind the Secret Mark redaction. Secret Mark has altered the original text of ch. 8-10 in a way that creates two resurrection miracles of Jesus, each following a prediction of the Passion, with another prediction of the Passion preceding an allusion of the Resurrection. This creates a foreshadowing of the Resurrection in each prediction of the Passion. Also importantly, the word used to refer to resurrection was changed from egerthenai "being raised" to anastenai "resurrection," and the emphasis on ethambounto "amazement" was also designed to foreshadow the amazement at the Resurrection of Jesus. So, we find the first prediction of the Passion in Mark 8:31 (which ends with the words "and after three days he will rise [anastesetai]"; cf. Matthew 16:21=Luke 9:21), and then six days later he gives a preview of his glorification in the Transfiguration (Mark 9:1-13), immediately after which a crowd came to Jesus and his disciples, "amazed" (ethambethesan) at him (Mark 9:15), and Jesus performs his first resurrection, which in original Mark (as attested by Matthew and Luke) was simply an exorcism of an epileptic child:
"... and the demon departed and he was healed." (*Original Mark; Matthew 17:18=Luke 9:42)
"... and the demon departed and the boy is left as if dead (hosei nekros), and the bystanders said he died (apethanen). But Jesus took him by the hand (kratesas tes kheiros), raised him, and he rose (egeiren auton, kai aneste)." (*Secret Mark; Mark 9:27-28)
This resurrection is an explicit foreshadowing of the Passion being followed by the Resurrection. Then the cycle begins anew in Mark 9:31 where we find the second prediction of the Passion which ends with the words: "...and after three days he will rise (anastesetai)." This is followed by story of Jesus teaching the rich young man (10:17-22), which the redactor has revised to add the notice about "Jesus looking at him loved him" in v. 21. The rich man is unable to unburden himself of his wealth and Jesus' disciples "were amazed (ethambouto) at his words" (Mark 10:23-24). Then the disciples went on the road to Jerusalem, and the redactor has added the words "they were amazed (ethambounto) and those who followed were afraid (ephobounto)" (Mark 10:32; these words are missing in the parallel account in Matthew 20:17-19=Luke 18:31-33). These two words later occur in Mark 16:5-8 of the two women who fled the empty tomb; they were "greatly astonished" (exethambounto) and "afraid" (ephobounto). This statement in Mark 10:32 is thus the second foreshadowing of the Resurrection. The cycle begins anew in Mark 10:33 with the third prediction of the Passion which ends with the words: "... and after three days he will rise (anastesetai)." This prediction is directly followed by the story of the resurrection of the rich youth, who had died. The language of this resurrection miracle directly parallels that of the first resurrection:
"... and the demon departed and the boy is left as if dead, and the bystanders said he died (apethanen). But Jesus took him by the hand (kratesas tes kheiros), raised him (egeiren auton), and he rose." (*Secret Mark; Mark 9:27-28)"There was a certain woman whose brother had died (apethanen) ... Jesus stretched out his hand and raised him (egeiren auton), taking him by the hand (kratesas tes kheiros)." (*Secret Mark 10:34:4)
This young man this then described as "rich" (plousios) and "the young man, looking at him [Jesus], loved him (ho de neaniskos emblepsas auto, auto egapesen auton), which directly connects him to the "youth" (nestetos; cf. neaniskos in Matthew 19:20) in Mark 10:17-22 who was the "rich man" of v. 25 (plousion), and "Jesus, looking at him [the youth], loved him (ho de Iesous emblepsas auto egapesen auton)" in v. 21, whereas in Secret Mark 10:46, reference also is made to "the young man whom Jesus loved" (tou neaniskou hon egapa auton ho Iesous). Six days after the resurrection Jesus teaches him "the mystery of the kingdom of God," which recalls the Transfiguration occuring six days after the first prediction of the Passion. The youth is dressed "with a linen cloth over his naked body," and then Jesus has a conversation with the sons of Zebedee where the redactor of Mark changed Jesus' Eucharistic foreshadowing of his crucifixion into a metaphor of baptism:
"Jesus answered them and said, 'You do not know what you are asking. Can you drink the cup that I shall drink?' They said to him, 'We can.' He said to them, 'The cup you will drink. But to sit at my right hand...' " (*Original Mark; cf. Matthew 20:22-23)
"Jesus answered them, 'You do not know what you are asking. Can you not drink the cup that I drink; or can you be baptised with baptism with which I am baptized?' And they said to him, 'We can.' He said to them, 'The cup that I drink you will drink; and with the baptism with which I am baptized you will be baptized. But to sit at my right hand...' " (*Secret Mark; cf. Mark 10:38-40)
This statement is possibly key to the other redactional passages of Secret Mark and canonical Mark: the central concept may be of baptism as a mystical union with Jesus in his death and Resurrection. That would explain why the young man is "dressed with a linen cloth over his naked body" -- he is dressed for baptismal initiation, and his death and resurrection qualified him for initiation into the "mystery of the kingdom of God". The concept is strikingly reminiscent of Romans 6:2-6 where Paul says "when we were baptised in Christ Jesus we were baptised in his death; in other words, when we were baptised we went into the tomb with him and joined him in death, so that as Christ was raised from the dead by the Father's glory, we too might life a new life." The concept is ultimately derivable from Hellenistic mystery religions which have initiation rituals uniting the convert with the dying and rising god. It is important to note that this concept is brought in sharp relief by a combination of Secret Mark with the canonical Mark passages absent in Matthew and Luke; the notion is virtually absent in the original Mark known to the authors of Matthew and Luke.
The connection between baptism and death/resurrection is also established by the word sindona "linen cloth" which is what the youth wears in Secret Mark for his initiation. The sindona is also the burial cloth that Jesus is wrapped with in his tomb (Mark 15:46). The Gethsemane youth who runs away naked in Mark 14:51-52 was also wearing a sindona. The classic mystery of Mark 14:51-52, before the discovery of Secret Mark, was: (1) Who was this bizarre youth who appears out of nowhere in the story, (2) Why was he almost naked? Secret Mark provides an answer, or at least a partial answer. This youth could have been the same one that Jesus resurrected in Bethany and had not changed out of his initiation clothes. On the other hand, this may have been another youth who was wearing a sindona because he was awaiting a baptismal ceremony like the Bethany youth. There may of course have been other material in Secret Mark that shed light on this question but which have not survived. And then there is the question about the youth wearing a "white robe" inside Jesus' tomb and his connection with the Bethany and Gethsamane youths.
None of this is really certain, of course, but it seems to explain a lot by looking at it this way. The Markan passages omitted by Matthew and Luke that I mentioned appear to work together with the known Secret Mark passages to construct a series of foreshadowings to the Resurrection, paired with the three predictions of the Passion. There is also a theme of death as baptism -- as baptism also is a symbolic death of the "old life" as one is reborn. The expanded edition of Secret Mark was then abridged and the more esoteric passages were deleted, but a few (such as the naked Gethsemane youth) escaped the notice of the later redactor to confound later readers.