Mr & Mrs,
We had thought about the Hills Labor Day weekend. Did it years ago and it was great.
Weather cools off nice and all the Sturgis traffic gone.
AND...lots of Rally beer left over that they blow out for a buck a can (this is last of season before most places close down).
Check out Rec. Springs just outside of Lead (SD). Cheap lodging, have gas, their back yard is straight trail access, and they used to rent atvs, so off road friendly. Not too far from Deadwood, which I think you would like to check out. The Heads (Rushmore) are a bit of a ways off, but if coming from MN, you could swing past them via Rapid; then on up.
Custer State is very neat too, but pretty big with no real gas, food, etc.
Not much in Sturgis after Rally, but Deadwood keeps pretty open, and they have an oyster bar and John Wayne's 70 something F250!
Probably not too exciting for you folks, but round here, the Hills are the best we get.
Might see you there...
-you will have to check map, but Needles Hwy is real pretty too, but again, a ways off. Just cannot recall right now if you can catch that with the Heads from Rapid, if you stay up that way.
Edit- Nope, Needles IN Custer.