We’ll be going to a concert on our first day, and will have the entire 2nd day open and are interested in doing something outdoors in May. This could be going on a scenic bike ride or heading up to the mountains to hike, etc. We’re willing to drive an hour or so if needed and could even stay the 2nd night outside of Denver (maybe a nice mountain resort?) before coming back for our flight in the early afternoon on the 3rd day, but also open to staying in Denver.

Any ideas? Also open to non-outdoor ideas if there are any must-dos.