Karen, I seem to recall something on the Red Sea from a high school Western Civ class. I think the "mainstream" non-fundamentalist thinking was that they crossed something like a marsh that existed in that day, where the tide went in & out at various times.
"Oh no the Egyptians are after us, and there's all this water in front of us! What'll we do?"
Later, after Moses raises his arms & all that for awhile, the tide goes out & the Hebrews walk across the leftover mud. The Egyptians try to pursue in their chariots, which of course get stuck in the deep mud... And the story gets exaggerated over the years until you have walls of water 100 feet high on both sides, crashing in on the hapless Egyptians (who all perish, of course) immediately after the Hebrews finish crossing.
The "Bible scholar" interpretation was something like that, I recall... My WC teacher said something to that effect in a class, plus I ran across that idea during research for a term paper. Hope it helps, might give you a place to start at least.
SpiderMonkey