The week leading up to Easter Sunday is the busiest week. The week after is slightly better. The parks will be extremely crowded -- but they are all open late. The MK will have 2-3 Spectro parades, Fantasmic at MGM will have 3-shows, etc. Always go to the latest show. At MGM they line up 1.5 hours before the first show. This past Easter, MK had Extra Magic Hours every day and was up until 3:00 am twice that week. Be sure to make all your ADRs. FastPasses will be gone at Noon for the most popular rides. I like using TOurGuideMike for his advice at Easter.