You can drive your private vehicle on the dirt-road tour thru Monument Valley, or there are several tour operators that will take you in their vehicles. Gouldings offers this service that can be arranged at CG check-in.
I think the 4 hour tour was $40. Private vehicles are charged an access fee but not sure how much it was. The thing that sold me was that the nearest town doesn't have a decent-sized grocery store but has 3 windshield repair shops.
The Gouldings tour provided a Navajo guide that was very knowledgable and entertaining. I would have paid $40 bucks just to sit and talk to that guy for a few hours.
Just a suggestion. (the view from Goulding's campground into the valley is incredible!!!)