As others have stated, you'll have two options for purchased EPs. Which one you'll need may depend on when you're going. If the crowds will be low, you may be able to get by with just the one use per attraction EP or none at all. Then again, with one day, you probably won't have time to re-ride much if you're trying to hit all of the attractions in both parks. Just make sure you get a park-to-park ticket!