We've been at WDW in Feb, April and May (unfortunately not in the same year). I recall February to be not too bad. We noticed an increase over President's Day, but it was still far from really crowded. April and May are good times to visit. The weather is warming-up, but hasn't hit scorchers that you can expect in summer. With Easter being early, you should be going at a good time. I don't think I've been there for Spring break. I think it's more likely the college kids would head for the beaches rather than WDW.