It wasn't clear to me whether you have a toad. If not, you will definitely want to rent a car with which to tour Yellowstone. Assuming there is a site at Grizzly RV in West Yellowstone for when you want to be there, you can leave the MH there, rent a car in West Yellowstone for the duration of your stay, and take day trips into YNP and even down thru GTNP to Jackson from there. They will be long days (8-10 hours or so, roundtrip) but plenty to see! Allow at least 4 full days for the combination of both parks; more is better.