It's been a few years since there but when we were there we stayed at Fishing Bridge. It was the only campground in the park with hook ups. As we rode both loops on the Harley we saw several campgounds in the park with no hookups but were great locations.
There is no scenery at the fishing Bridge campground. it's almost like a parking lot.
If you have a good generator and batteries I would now perfer the outter campgrounds. a lot more rustic, like the park.
You should call ahead for reservations to be sure. With the price of fuel I am sure they are no where as busy as they used to be in the late ninety's.
Be sure to eat at the Yellowsone Lodge, it's a real treat.