I went through there when I was a kid. About 13 I think. It was one of the best vacations I ever had. That was almost 40 years ago and I still talk aout it with my mom. I hear it's changed a bit at Mt. Rushmore. I guess they moved the viewing area closer. As for the badlands, I don't think anything has changed there for 10,000 years! This year we are going to Disney. Three more days in fact. Probably be a bizillion people there. But we tend to be more laid back by the pool people and pick our times.
Try to go to one of the caves to the south of Rapid City, Not the tourist trap ones---the Nat'l Park ones---Jewell cave & Wind cave (if I remember right). Go see the air museum at Ellsworth AFB; don't know how much longer it'll be there as Ellsworth is on the chopping block. Sturgis has an ol' historic fort just outta town. Hot Springs SD has a GREAT indoor mamoth site (archeology). In Rapid they have a great miniture golf course. Mt Rushmore on the 4th of July nite is great.
you wouldn't happen to be a feeder driver here in Florida would ya?
One of the guys that comes to our building is off on a cross country month long (Now thats a vacation) trip. Showed me his brand new, sweet rv (its nicer then my house and almost as big)and was heading west, pretty sure he said all the way to California.