Whilst on our way to Yellowstone we stopped at the Wyoming Information Centre. This was a great call as they explained all of the roads that are currently closed in Yellowstone. This saved me a lot of miles as I intended entering through one of the closed entrances. They also suggested a visit to Devils Tower on the way.
This is a fantastic spot, a huge tower of rock that you are able to walk around, go climbing on if capable and generally have a good time.
The parking for RVs and large vehicles is great
It is another worldly experience, Steven Spielberg obviously thought so as he filmed "Close Encounters of the Third Kind" here.