2 years ago I went 1 day and did both parks. I didn't get express passes (well I got them at the ride itself with my entrance ticket) and I didn't stay onsite. I also took Mears from Disney. I first did IOA and then Universal. I was able to do: Dueling Dragons twice, the Hulk, Spiderman, Cat in the hat, Jurassic Park, both water rides (Popeye and the other one), MIB, The Mummy twice, a pet show, ET, Shrek, Back to the future (skip this one!), Twister, part of Blues Brothers, Terminator, Earthquake and I think that's it. I must add that I did everything on commando, had a quick service lunch and took no pictures, didn't film. Plus I was solo. But I'm happy I was able to do so much in so little time. This year however I'm going 2, maaaybe 3 days to be able to relax a bit more and do and see everything. But I'm still not staying on site or buying express passes when you can get them for free.