Golf carts are "nice to have" but not a "got to have" at the Fort. The Fort is flat and very walkable. There are nice paved walking trails everywhere and it is also a great place to ride bikes. Busses circulate the Fort as well. I don't want to spend the money on a cart so I don't get one but many folks do.
However, if you decide to rent a cart you can use an off-site vendor such as Kenny at Tee Time Golf Carts or rent directly from Disney. A regular 4-person cart from Kenny runs about $35/day with a 4-day (or so) minimum. A Disney 4-seater will run about $65/day with a 1-day minimum (no hourly rentals). There are several threads on the main board discussing Kenny and golf carts (it's a popular topic).
As for other things, I would establish a fund to buy Fort merchandise to decorate the RV. Everything from Chip & Dale salt & pepper shakers to foot rugs to fridge magnets to coffee cups (and on and on). Pens, shot glasses, key chains, etc. Campers seem to go beyond other resort guest when it comes to the merchandise. I mean lots of resort folks get a themed t-shirt but how many guests at the Contemporary get a themed spare tire cover?
Bama ED
PS - RV'ing is a lifestyle choice and not necessarily a financial one. But people seem to like the idea of visiting Disney and sleeping in their own bed.
PPS - I love Yeeha Bob too. Where does he find the energy each night?