Hi C&M,
That's kind of a tough one to predict because the schools in the west (Washington, Oregon, California, Nevada, Idaho, and Arizona) go on spring break anytime between mid-March and mid-April, so even though you'll be going after a holiday time, you still may run into heavy crowds due to spring break. Add to that the fact that since you'll be going on a weekend, you'll get the local weekend crowds in addition to the springbreakers.
Last year we went mid-march because my son was on spring break from his school, and we thought that most schools don't go on spring break until April, so the crowds shouldn't be too heavy at DL, or so we thought. Boy, were we wrong! It was so packed that we stood in line all day, everyday, and we only got to ride about 3 rides per day, and that was using FastPass. It was a bummer.

And, when we went it was Monday - Thursday.
Anyway from what others told us, it was packed like that the rest of March and thru April due to springbreakers.
If you can try to go the first week in May (before the schools start their summer breaks), or if you want to go the week after Easter, try to go mid-week (Mon, Tues, Weds, Thurs) because the crowds are always heavier on Fridays and the weekends.
Good Luck!
