I'll be honest. We stayed at Animal Kingdom Lodge when my kid were 9 and 6. They are pool loving kids, so we definitely got to a point in the afternoon they got hot and tired and just wanted to come back to the resort and swim. However, we ALL got super lazy and comfortable once at the resort and we only made it back to the parks ONCE for the evening. I can't believe so many kids are totally up for going back to the parks after the break.
We had a car, but the hassle of parking and more shuttling and walking from parking lots, I think it's easier and more comfortable over all to take Disney transportation. Last November we stayed at Pop, and the bus system worked great. I don't think we'll ever be getting a rental car again.