The San Juan Skyway is awesome, so is the Durango area, try and take the Silverton railroad from there to Silverton, it's an old steam locomotive, and the scenery is breathtaking, you can also go to Mesa Verde National Park, the ruins there are very interesting, and many you can get right into. Ouray is not far from Durango either and has some hot springs. I also enjoyed the Pagosa Springs area. If you have access to a 4 wheel drive vehicle or can rent a jeep for the day, some of the back roads bring you to some interesting old mines, but before warned that just because they say a road is say 20 miles long, it will take you 3 times as long as normal to do that 20 miles. That part of Colorado is beautiful.