King:
A fun thing to do if you're remotely mathematical/logical in nature is to calculate how long it would take a single column of 3 mil people, walking 20 abreast, to pass a single point, just to see how long it would take to enter (not even exit) the parted Red Sea... Assume they walked 3 mph (a fast pace), and walked a distance of 3 ft apart (crowded).
MP->King:
Armies were lucky to walk 10km in a single day in ancent times. There is no way people carrying stuff would walk that fast. If anything it would 1 days for the entire group to pass a point. I think i read somewhere they were lucky to march 10Miles on a good day.