It's always good to know the alternatives.
As far as not having a vehicle to drive - get a tow dolly. That way you can tow any vehicle without having to get a vehicle modified for a tow bar and brake buddy.
We have had good luck without having a car. Renting a car for a day has not been a problem anywhere we've been (thanks enterprise - they pick you up btw), or we camp on the gulf, on the river, or on the metro (DC). Don't get me wrong, we want to get a dinghy, but I don't think it's required or necessarily cost effective (esp at WDW)....