It's going to cost about $2000 (if not more) to rent one for two weeks, not including gas. They get about 7 miles to the gallon, so plan on another $500+ for gas.
They are very different than driving a car or minivan. They sway, they rock, they are cumbersome to manuever in traffic.
It's much less to fly. If you don't want to fly, drive and stay in a nice hotel every night, it'll still be less costly, even if you rent a car!
As far as parking at the hotels, they all have oversized vehicle parking. If youa re spending that kind of money for a rental, I'd be staying at the campground though. It's about the only way you'll get your monies worth. Just be aware taht they are a lot smaller than the average hotel room, so you might get on each others nerves that much more quickly.
Anne