I would say for the amount of money you will drop its worth it to wait until the kids can ride what they want and walk a ways without getting grumpy. I recommend a meal pass (if you look at the price on the menus you may never eat). We stayed in the park, but even that is 30 minutes or more from where you will want to be depending on where you stay. Expect a lot of 'down' time, travel, waiting in lines, etc. I think you can figure a day per park you'd like to do and assume $500-600 per person per day minimum. You can definitely go over that though. I'd look into packaging room, flight, and food into one. I think we went through Southwest airlines and it may have cost a few hundred more in the long run but took a ton of stress out of the trip.