Personally, I say absolutely get the park hopper. It is more money, but we've found that often we will start off in one park in the morning, go back to the room to rest and then do a different park in the afternoon. It's easy getting between parks so that is no problem. Also, with little kids we've found that although there are attractions they definitely like at Animal Kingdom and MGM, we usually don't spend an entire day just in those parks. We like the flexibility of switching and if there is a ride you just have to do one more time at Epcot, you can hop back over without using another day's ticket.