The Exodus narrative was composed during the Babylonian exile and likely finalized shortly after the exile ended. Jews view the narrative as reflective of the diaspora Jews who were attempting to preserve their culture now that they had no land nor Temple in Babylon. Thus the Jewish practices and history were combined with folklore that was heavily slanted to give the customs of the Jews a religious connection.
With that in mind, the answer is no. The 40-year trek of millions of people crossing the Sinai peninsula as found in Exodus is not viewed as literal in Judaism. If it were literal, a crowd that size would still be crossing the Sea of Reeds while the first Hebrews were approaching the traditional site of Mt. Sinai.
While historically there is evidence that some of our ancestors likely lived in Egypt under the Hyskos dynasty, the following dynasty did endure a series of slave escapes, perhaps three or more, in which those welcomed under Hyskos rule left for the Fertile Crescent area and beyond.
While there are some Jews who might give this a literal reading, the idea that his took 40 years is taught to teach a religious lesson more than report on history. It teaches the lesson that a new nation arose from the slaves that left their previous life behind, like one generation bringing forth a new, totally free one. 40 gets used a lot like this in Scripture, with one situation being renewed into something totally different.
As for the snake used by Moses to cure in the wilderness, it appears to be a recurring symbol of rebellion. When Adam and Eve rebel, the narrative has a snake in it. When Pharaoh rebels against God, Moses' staff becomes a snake that devours the snakes of Pharoah's magicians. When the people rebel during the Exodus, they are punished by snakes and healed by seeing a symbol of a snake on a rod, as if reminding them of the rebellion of Adam and Eve.
Recall that the Torah is one book, and that it originally ended with Numbers. Deuteronomy is one of the final redactions to the Torah, added sometime after Numbers was completed. While definite certainty doesn't exist about this, it is not unlikely that the snake is a purposefully employed narrative device. Torah begins with a rebellion (symbolized with a snake) and originally ended in Numbers with a snake image reminiscent of the Genesis story.
It may be that this was a commentary on the destruction of a snake idol by King Hezekiah, an idol that was worshipped by some Israelites as mentioned in 2 Kings. These Israelites may have tried to legitimize their cult by claiming this was the very image forged by Moses, but it is quite likely that this was a popular myth about the idol's origin. The use of the symbol in Genesis through Numbers may be based on that image, given the fact that the snake does seemed to be used as a device in Torah each time disobedience or rebellion arises.