This overlooked little campground had sites available when the others in the park were full. As with the other Yellowstone campgrounds, it still pays to make reservations at 7:00 AM Mountain Time six months to the date you arrive at Recreation.gov. It's convenient, as it is located between Mammoth & Norris.
Our trailer is 29 feet long including the tongue, and we found a spot by entering 30' in the search filters. While most sites were rather short, there were rigs much longer than ours there.
No hookups, generators not allowed, pit toilets - but you're in the park!
Note: We explored the new North Entrance road between Mammoth & Gardiner. 10% grades, 15 mph hairpin curves. Yikes!