Yes, avoid weekends at all costs! I worked there one summer and it is super busy on the weekends! Monday and Tuesdays are pretty good days to go. It will still get busy by noon, but not as bad as a weekend. We just went this past Monday. We got there at 8:30 (stayed at a resort and planned to get there at 8, but our POFQ bus picked up at EVERY RS stop and then had problems with the wheel chair lift at the last stop!!! So plan accordingly!) and got all the rides done a few times, plus once around in the lazy river, and a fair amount of time in the wave pool by 10:40. We ate lunch and were out of there by noon, when there was a CRAZY back up of cars and busses!
Go on a Mon or Tues, get there early, have fun, eat, and go home happy!