Cedar Point is a park you do in a day, and then the next morning to do favorites one more time.
Similar thing with USF/IOA. You take 1 day at each park, then the 3rd morning to do favorites.
You can do both parks in 1 day if you get there early, go in commando mode, and don't care about most of the shows. But if you want to take your time and see most of the things, then 2 full days and the 3rd morning are what is needed.
With CP, I check into Breakers Express the night before so I have my tickets and early entry pass. I spend the entire day at CP, the night at BE, check out in the morning, visit CP one more time, then drive on to another destination.
With USF/IOA, most pre-check into an onsite hotel early in the morning, get their magic keys, visit a park, check in for real at 4pm, have a nice dinner, visit the pool. Visit a park the next day, visit pool, sleep the last night. Visit favorite park in the morning, check out at noon, fly/drive home.
2 nights at each hotel, just with USF/IOA, you pre-check in the morning to get those magic keys, whereas with CP, you check in the night before.