we used a stroller everyday at every park for the 4 year old. we were both set against it but then we got there the first day and decided why not. the strollers you rent at MK, Epcot and AK are all basically the same, the child is pretty sheltered from rain but they are not too comfortable to sleep in. the one at MGM is less sheltered but more comfy to nap in. our little one does not nap either but napped everyday in the stroller. my suggestion is get the stroller because the excitement, standing in lines, etc is going to wear him out enough. by the middle of the week he will probably be overall tired enough that the stroller will help make it through the day. also, we took a backpack, 4 waterbottles with straps and 2 cameras into the park and the stroller made carrying all this stuff very easy. we even left it on the stroller while we were on rides and had no problems. One more thing, if your little one has a drink and a snack and sunglasses and a little fan, you give all that stuff to him at the start of the day, he has it in the stroller with him and you are not stopping every 15 minutes to give him something.