Last year we went that week in April (remember Easter was at the end of March). It was still peak season, and just before the kick off of the 50 years thing. The crowds were rather light, and the trip was great! It was worth it to pay a little more for peak season prices to have the parks so empty! Our last night was the start of the next season, and the crowds were heavier.
I think there will most likely be some crowds, (especially between 11am and 5pm) but not nearly as bad as the week leading up to Easter. You'll also be likely to get great long park hours. I love the MK after dark...being at the MK until nearly midnight was really cool. The lines are almost non-existant. The Haunted Mansion at night is one of my favorites!
The best way to take advantage of extended hours is to take a break in the afternoon - go swimming, nap..then have an early dinner and a great evening. If you want to see the parade, watch the latest showing -use the first evening parade for easy ride access.
Enjoy!
