I really don't understand the need for Noah's Flood to be an actual event.
If I was looking at it in terms of an allegory, it suggests that punishment is reserved for the wicked and sinful while the innocent and just would be safeguarded and spared.
As a literal story, it says a lot less than its allegorical. It also implies that mankind is judged as a group, with only a chosen few spared.
Considering that Noah was only a couple of generations removed from Adam, I find it amazing there was not much sorrow in the passing away of his family(the people around were his cousins, not just 'friends' but actual blood relatives)
Also, it does not seem like it was necessary to drown the entire world when a flood that engulfed the region would be more than sufficient to kill mankind. Do you really think that a handful of Noah's relatives made a bee line to America? Just to argue they made it past the Himalaya's is asking a lot for this time period--how would they even know how to survive, given that they were raised in a river valley?