It has a been more than a few years since I was there then, but at that time it did get very crowded, especially Magic Kingdom. But there were long hours at the parks too, so we would go early, and as it became really crowded around mid-day, leave , and return later on. I guess if I was doing it now, I would still go early, book my fastpasses for mid-day hours, then leave for a while and return later.