I'm going to WDW next month with my DH and our two DD's. We plan on going to Harry Potter World. We will be getting the park hopper ticket for two parks, and will be skipping the water park. I'm wondering if it's possible to do Harry Potter World in one day if we know ahead of time we probably won't make it on all the rides? How about if we're there from morning until closing? I don't want to buy a two day park hopper in case we don't want to go an extra day. I was told we could upgrade to a two day park hopper the day we're there if we change our minds.