I did 2 of them and part of and or parallel to 2 more.. and I have not been east of South Dakota.
I sped thru a lot of Highway to the Sun, trying to make time till I finally said to me hey why dont you try to see this at a slower pace.
I think there are many more that qualify.. Sturgis to Deadwood or Spearfish Canyon.... and Ortega Hwy in Cal...rode all of them.
We have a local one here that is getting very well known in the North west...Westside Road..