Whether or not those who composed the Exodus story had an allegory in mind, the Gnostic Christians (who some say were the original Christians) certainly interpreted it that way. The Literalist Christian Hippolytus tells us that Simon Magus (of the Simonians, a Gnostic sect) interpreted the words of Moses and the Pagan poets.
They interpreted ‘escaping from Egypt’ as ‘escaping from identifying solely with the body’ (in other words, identifying more with the spirit or soull) and the Egyptians represented those who are ignorant, or ‘without Gnosis’ - in other words, without the spiritual knowledge of how to do that, gained by secret initiation.
The Literalist Hippolytus, (2nd century) who opposed the Gnostics, said dismissively of their teachings: “Those who are ignorant .... are Egyptians. And this, they assert, is the departure from Egypt, [that is] from the body.”
He also refers, when talking about the Naasene Gnostics, to their habit of calling themselves, to mark their three stages of initiation, respectively: ‘the chosen, the called and the captive’.
Freke and Gandy give some more detail about this:
The name Jesus itself comes from Exodus. In Greek, the Hebrew name ‘Joshua’ [who took over from Moses] becomes Jesus....
....Early Christians were well aware of the parallels between their Jesus Christ and the Jesus of Exodus. Justin Martyr (c 100 CE) for example, explains that the Christian Jesus will lead his people to the Promise Land just as the Jesus of Exodus led his people to the Promised Land.
In fact, in his Dialogue with Trypho, in the chapter entitled ‘Joshua was a figure of Christ’, he mentions Joshua 38 times in an effort to persuade the Jew Trypho of his point.
Justin Martyr traces the motif of the cross to Exodus where Moses holds up the serpent on the cross and says: “If you look at this image, and believe, you shall be saved by it.”
This is reflected in John, where Jesus is made to announce:
“The Son of Man must be lifted up as the serpent was lifted up by Moses in the Wilderness.” John 3:14
Crossing the Red Sea was interpreted as baptism. Paul, who is suspected of being a Gnostic anyway, appears to be supporting that view when he says:
“Our ancestors passed through the Red Sea and so received baptism into the fellowship of Moses.” 1 Corinthians, 10: 1- 6.
So from this we can see that the Christian Gnostics were following something very similar (but not identical) to the Greek Gnostics and their Mystery religion.
This is Wiki on Mystery Religions:
http://en.wikipedia.org/wiki/Mystery_religion
The term 'Mystery' derives from Latin mysterium, from Greek musterion (usually as the plural musteria μυστήρια), in this context meaning "secret rite or doctrine." An individual who followed such a 'Mystery' was a mystes "one who has been initiated," from myein "to close, shut," a reference to secrecy (closure of "the eyes and mouth"[or that only initiates were allowed to observe and participate in rituals. Mysteries were often supplements to civic religion, rather than competing alternatives of such, and that is the reason these are referred by many scholars as "mystery cults" rather than religions.
The Mysteries were thus cults in which all religious functions were closed to the non-inducted and for which the inner-working of the cult were kept secret from the general public. Although there are no other formal qualifications, mystery cults were also characterized by their lack of an orthodoxy and scripture. Religions that were practiced in secret only in order to avoid religious persecution are not by default Mysteries.
(Btw, imho the jury is very much out on whether the last sentence of first paragraph is true. Certainly in the case of the Christian Gnostics, there is evidence that they could have been the original Christians. It's Literalist history writers who perceive them as otherwise, and the same could be true of the Greeks)
As it says, much secrecy accompanied these initiation rites and also little was written down. But we have enough to know that the initation was comprised of three stages that were linked to three elements: water, fire and air.
So in the next post, I’ll explain how this mirrors the Gnostic Christian initiation rites and how they used the story of Moses as an allegory to mark each stage. From that we can start to understand how all the Gospels, and possibly the NT, was one huge collection of myths, or allegories (or parables as Jesus called them) with next to no histriocity at all, apart from that to be gleaned from the background.