BTW, the echoes are Daniel in Luke 21:24 are slighter than the allusions to other scriptures. In fact, this verse is a Lukan modification of the passage about the "abomination of desolation" (= Mark 13:14) which replaces the Danielic reference (as made explicitly in the Matthean version) with a specific application, i.e. the situation of Jerusalem surrounded by encamped armies. The notion of Jerusalem being trampled on by the nations for a predetermined period of time is a Danielic one (specifically relating to ch. 7-9), but the wording more closely resembles other scriptures that were probably drawn on more directly.
Tobit 14:5-6 LXX: "God will have mercy on them and he will bring them back into the land, and they will build the house, not like the former one, until (heós) the appointed times of the age (kairoi tou aiónos) will be fulfilled (pléróthósin). Then after this they will return from their captivities, and they will build Jerusalem honorably. And the house of God will be built in it as a glorious building for all the generations of the age, just as the prophets said concerning it. Then all the nations (panta ta ethné) will turn back truly to fear the Lord God".
Zechariah 12:2-3 LXX: "In Judea, there will be a siege against Jerusalem. And it shall be on that day I will make Jerusalem a trampled stone (lithon katapatoumenon) for all the nations (pasi tois ethnesi); everyone who tramples (katapatón) it when mocking shall mock. And all the nations of the earth (panta ta ethné tés gés) shall be gathered against it".
Romans 11:25: "Israel has experienced a hardening in part until (akhris ou) the fullness (pléróma) of the nations (ethnón) has come in".
Luke 21:24: "They shall fall by the mouth of the sword, and shall be led captive to all the nations (ta ethné panta), and Jerusalem shall be trampled down (patoumené) by the nations (hupo ethnón), until (akhris ou) the appointed times of the nations (kairoi ethnón) will be fulfilled (pléróthósin).
The link to Romans seems to be more a matter of similar diction, rather than involving a similar eschatological concept, so I do not think it necessarily lay before the author's mind, but the passages from Tobit and Zechariah are quite close. When combined with the reference to the Gentile fourth kingdom "trampling" others for a period of "times" in Daniel 7 LXX and with the reference to Jerusalem being desolated during a set period of "times" in Daniel 9 LXX (with the interpretation of the "abomination of desolation" in ch. 9 being connected with the situation of Jerusalem "encamped by armies", cf. also the siege mentioned in Zechariah 12:2-3), you get pretty much what is in Luke 21:24.
BTW, the situation described in the Tobit passage is not the return from Babylonian exile, other than the first sentence. First God "brings them back into the land," i.e. the return from Babylonian captivity, and then "they will build the house, not like the former one," this is a reference to the rebuilding of the Temple but not to its former glory (Tobit was written prior to the later Herodian rebuilding of the Temple). The reference to the Jews returning to their captivities and building Jerusalem honorably is thus eschatological, having in view a more glorious Third Temple with all the diaspora returning to Jerusalem and with all the nations turning to God in worship (as it is in Zechariah). This is the eschatological event that would not happen "until the appointed times of the age will be fulfilled". The scenario in Zechariah 12-14 is one of Jerusalem being surrounded by encamped armies and then God will give power to the leaders of Jerusalem so they will consume all the surrounding peoples with Jerusalem left intact (v. 6), with God destroying the surrounding nations (v. 9), and then "the survivors from all the nations that have attacked Jerusalem will go up year after year to worship the King, the Lord Almighty, and to celebrate the Feast of Tabernacles" (14:16). This gives some insight into the motivations and beliefs of the Jews who fought against the Romans in AD 66-70 and why they felt they would be victorious; they believed that the war with the Gentile armies fulfills scripture and they have the reassurance that God would wipe out the armies miraculously. Luke alludes to these same scriptures but gives a very different application; the Jews should flee for their lives and not stay behind to fight, for Jerusalem and its temple would indeed be destroyed (cf. Luke 21:5-6).