The area around Mt Rushmore is beatiful. My stepsister lives in Keystone, and I've been out that way a couple four times.

Next time you need to take a dip in Sylvan Lake - the thing has thermal layers about every 18". Last time I was out there, my toes, less than 6' underwater were freezing tho my head was quite toasty. I swam around that rock, and it's much further than it looks.