We just got back yesterday from Orlando and spent a total of 3 days at USF/IOA. The crowds weren't bad at all and we were able to do everything in both parks and we didn't even stay until closing. The first day at USF, we were there early and they opened the gates at 8:30 instead of 9:00. We rode everything and even did the Mummy and MIB 3 or 4 times. IOA was a little more crowded (lots of school groups) and the gates didn't open till 8:45. ??? We rode Spider-Man 3 times in a row with no wait at all right after the park opened. The waits for the coasters weren't even that bad. I never saw a wait of more than 30 min for Hulk and Dueling Dragons was more like 15 most of the time. I definitely think you will be fine doing USF in just one day. But I would get there early and try to do Mummy and Shrek first thing.