The nearest one with electricity is a Federal campground called Rex Hale, about 16 miles east of the east gate into the Park. There is another fed campground with elec. at Wapiti, about 22 miles east of the Park entrance.
Inside the Park, Bridge Bay campground has a good dump station and water, but no elec. and you definitely need reservations for a rig as big as yours.
If you want to explore Cody, WY before going on to the Park, the Ponderosa RV Park is your best bet (IMO) and again, reservations are a must.
Or, you can go through the Park to West Yellowstone which is tucked up next to the west Park gate, and there are several rv parks in town to choose from..with reservations.
Our preferred choice is about 15 miles south/west of the West Yellowstone, called Henry's Lake State Park, which has it all. View, hookups etc.
