We went mid to end August last year and the crowds didn't seem so bad, even with the free dining. We made full use of the Fast Passes, and managed to ride on Expedition Everest four or five times on each of our visits to AK with minimal wait times.
A couple of things that we would recommend are:
(1) If you want to eat Table Service meals in the evening, book them in advance as on a number of occasions, people who turned up could not get a table.
(2) Pace yourselves - it is very hot and humid, but make sure you have some shows planned to get out of the sun.