We are a family of 7 and we love the DVC resorts. You can stay at BWV or BCV in the Epcot area. The kids can just hop a boat or walk to Epcot and MGM. Buses to AK, MK and DD are pretty frequent. My 2 oldest now 17 and 14, have been going out on their own some since they were 15 and 12 (of course they have to stay together).
OKW is also a great DVC resort, and our home resort, the rooms are quite a bit bigger than the other DVC resort rooms. The only drawback for me is you have to take buses to all the parks. We still have a little one in a stroller and it gets to be a pain to unload it and fold it evertime we get on the bus.
You could also stay at Ft wilderness in a cabin. They sleep 6 and have a full kitchen. One drawback is there are bunk beds in the master bedroom, and in the DVC resorts there is only a king in the master and the other beds are in the living room (fold out sofa) and in the 2nd bdrm.