My Mom has trouble walking, so I know exactly where cars can and can not go at Ft. WIlderness.
Every "camper" gets a car ID which you put in your windshield. There is room for one vehicle at every cabin "campsite." While you can drive around most parts of Ft.Wilderness, the "main" area -- near the Hoop-Dee-Do and the access to boat service -- is roped off and only open to foot traffic. If you want to take the boat to the MK, for example, you would have to use a Ft. Wilderness bus or walk down to the boat area. In general, camping loops are closer to the boat area and most of the cabin sites, added years later, are farther out.
The Meadows Trading Post has a few "10 minute" spaces for cars so you can run in during morning for coffee. There is also a space near the laundry facility for the cabins. If you want to go anywhere outside Ft. WIlderness you can take your car and park in THAT lot -- at the MK, Epcot, etc. You can also get a bus to the main entrance of Ft. Wilderness and then take another bus to the parks. Descriptions of transportation troubles usually refer to travel "within" the campground as it is large and the buses make lots of stops. The pace overall here is slower; this may be seen as a problem for some and a plus for others.
I believe the golf carts come in two sizes but I can't recall the rental cost. Lots of families zip around in these and there are lots of places to park them.
Ft. Wilderness has one large pool, adjacent to the Meadow Trading Post, and a smaller pool near the cabin loops. Both pools are basic and neither has a slide. I believe the main pool is guarded. When we visited last March, the cabin-area pool was heated enough that we could swim even when it was cool.
Hope this helps!