We went to Seaworld,
Legoland, and DL in early-mid October 2007 and I specifically chose that time because I heard it would be less crowded. For some reason DL turned out to be extremely busy mid-week. Even LL turned out to be really busy on the day that we went and there were really long lineups. I heard people saying it might have been due to school breaks in nearby states (I think I heard Arizona and Utah?). Apparently the crowds were low the week before and even the week after we went, so we just picked a bad time to go! I think if the times that you go don't coincide with the school breaks then you should be fine. I would try to plan LL and DL for mid-week because of the ride lineups but there are not really any lineups at Seaworld so the weekend should be fine for that. Hope this helps.