We stayed at KOA Mountainside in June 2020. Its 8.4 miles outside town. Lots of elbow room between sites. Long pull throughs. Weak cell signal, weak wifi.
We drove around looking at other places.
Yellowstone Park / West Gate KOA. Spaces look very tight.
Yellowstone Grizzly RV park is way above and beyond the best. Absolutely beautiful.
Right outside the gate.
Inside the park:
On the webpage it seems they can only accommodate vehicle + rv total lenght 40'.
https://www.yellowstone.co/maps/campgroundmap.htm
https://www.yellowstone.co/camping.htm
(See the campground/vehicle size description below the tables)
We drove through Madison, Grant, Bridge Bay, and Canyon. They were all tight.
We are 51' TV + RV(5th wheel 35').
Most I would not even attempt to park in. Some loops I would not attempt to drive through with our RV. It seems like all the sites are more suitable for travel trailers and popups than 5ers.
Fishing bridge, (the real RV park) has been closed for the last year (and this year). We drove by it. They are doing a LOT of construction on the main road. We drove into the parking lot. The road in is closed. From what we can see they have a ways to go yet.
Drove by Mammoth Campground. It is closed. There is a GD Reflection just inside the gate on one of the sites. We are guessing it probably belongs to a work camper, employee or host?