For Rushmore, I suggest Custer's Gulch RV park which is on the east side of Custer, close to Custer State Park. a bit pricey at $60. but well run and nice owner/operators. Or, Custer State Park itself, Game Lodge campground,but get your reservations NOW for that one.
For Yellowstone, we like staying about 15 miles south of West Yellowstone at Henry's Lake state park, very nice location, but get your reservations as soon as you can.
TexasShadow
Holiday Rambler Endeavor LE/ 3126B Cat
Sometimes BMW K75 on Rear Carrier
Jeep Grand Cherokee or 2016 Ford XLT 4x4 super cab with 8 ft bed
M&G aux brake system
854 Watts of Solar Power
Always remember you're unique, just like everyone else.