Grace:
Fort Wilderness spreads over a mile from its Outpost to the marina. Asking about transportation around this vast resort even if you didn't have a mobility issue is prudent planning.
Our family typically tows our own golf cart when we visit. This not only allows us to get from our campsite to the marina to take the boat to Magic Kingdom but also the Outpost Bus Stop where we can catch a Disney bus to the other three theme parks, Downtown Disney and the water parks. But honestly, the reason we take it is so we can enjoy "looping" and looking at all of the other campsite loops not to mention admiring other camper's RVs. If you don't own your own golf cart, you can
rent one at Fort Wilderness. Advance reservations aren't always necessary, but with the hot weather in July, I would recommend calling 407-824-2742 if you're the least inclined.
If you're only going to use the golf cart to get to the marina or the Outpost, you'd probably be better off simply using the internal buses at the fort. There is a bus stop within a few minutes walk of every campsite loop.
Wishing y'all a magical vacation!
Whitney