We went last year the week after Easter, it was our first trip, so I really researched where and when we wanted to go. Typically, we would go to EMH at the park, stay until 11-ish - when the parks started to get crowded, then went back for an afternoon rest. At about 4 or so, we went to another park, usually the EMH that night. It worked really well for us, with the exception of Epcot. It was very crowded there on EMH day. All of the other parks, we never waited more than 10 mins for anything. We also followed the TGM guidelines, go straight to the ride you want the most, get a fastpass, then ride in standby and return later for another ride.
Hope you have a great time!