Our trip is planned for April 14-21st (spring break for schools in MA!). I've been keeping tabs on TouringPlan's crowd calendar for that week, and overall the parks look to be moderately crowded with projected crowds of 5's and 6's during the week. It certainly looks better than week at end of March and week in early April which are projected to be 9's and 10's!
Still, I have clear touring plans each day so make sure the crowds don't affect us as much. Fingers crossed I get the fast passes we want though....that feels like the key to making my plans work!
Oh, and I've scoured the boards to find info on impact of the Star Wars half marathon which is later that week I'll be there. Seems like there isn't that much impact on crowds in the parks, but traffic can be impacted a bit.