When are you going. Not that it should matter if you have the front of line. You can easily do both parks in one day if you know which rides and shows interest you. Have fun
Depends on when you are going. Later on in May there will alot of school groups there on Thursdays and Fridays. If you are going in the middle of summer it might be hard to do too.
If you have a limited amount of time and don't mind missing alot then I think you could do both parks in one day.
I'm doing the same on May 17, got Express Plus Pass and plan on hitting all the major rides & shows in one day for both parks...plus Dueling Dragons is not open so that helps..otherwise would have to ride both red & blue.
Start in IOA doing the thrill ride tour. This can be done by noon if you arrive early skipping Dudley and Popeye. Then head over to USF and use single rider line for the Mummy and MIB.