My biggest thing, is what some others have said, take time to relax during the day. Makes for much happier Parents and kids.
Stay onsite
Get to the parks when they open and leave after lunch for the break. You'll have gone on most the rides just as the bulk of the people are walking in.
Budget, budget, budget. It's so easy to get carried away there.
Do your PS's at 90 days, you will get the times you want.
Go with the frame of mind, you won't see everything and that you will be back.
Comfy shoes and I agree ladies, get a pedi, you feet will love you for it.