The bottom line is if you add up all the coroborating evidence to the Biblical Exodus record you have enough to provide a significant amount of evidence that the event occurred. As for the population, there's a lot of speculation on both sides of the debate. I go with the corroborating evidence of the debris in the Nuweiba sandbar in the Gulf of Aqaba and the other coroborating evidence in the region including the significant split rock with dried up waterway, the Mt Sinai burnt top mountain, et al, et al and all in accordance with scripture.
I know this thread is not about this coroborating evidence. My point is that we shouldn't be too disturbed by the problems regarding the population when this will likely not ever be resolved. Imo either the figures are off some how or that the condition of the hard working slaves was such that they were well able to do the feat that the larger number calls for. These people were physically fit for a robust journey. They were given a good head start and there was ample area at the beachhead at Nuweiba to accomodate a large number of people. Also the topographical terrain of the beachhead at Aqaba was precisely as what the Bible describes for entraping the host of migrants. No other site fits the ticket.