School will be out so expect long lines. Plus, many out-of-towners.
We have annual passports (they often have promotions where you buy one day and get a whole year for free), and recommend going early. USH has two portions: the Upper Lot, and the Lower Lot. The LL typically opens later than the UL. The UL and LL are connected with a series of long escalators, so to save time, you only want to go to the LL once.
Go on the Studio Tour (the backlot tram tour) on the UL, then go to the LL for the Revenge of the Mummy, then the Jurassic Park ride (expect to get wet -- a poncho is a good idea), and anything else you want to see or do at the LL. When you finished the LL, go to the UL. Be sure to see Water World (a live action stunt show).
Have fun.
Woody