Denver to Rapid City
Looks like there are a couple of main possibilities with only a few miles difference between them. Going via Nebraska (385/79) or Wyoming (here a few alternatives for doing Cheyenne-Lusk-Rapid City). ...
Forum Discussion
I go back & forth from my CO home to my SD home a couple times a year and haven't found a big reason to use one over the other (unless I know one route has a major repaving project going on). Just for variety I use one going up and the other coming back. I25 N to 18/85/18 to Hot Springs or I76 to Sterling/Sidney, Neb & 385 to Hot Springs. In either case I make sure to avoid the Denver area during rush hours.
