Heading for Colorado's mountains via US 50, a nice ride in itself, brings you to Pueblo. An easy ride up to Canon City sets you up for some good riding. US 50 continues from Canon City up to Salida along the Arkansas River, through the Arkansas River Canyon. While you're spending time or just passing through Canon City, you absolutely will want to take a ride over Skyline Drive.
Another route into the Rockies is up US 24 through Woodland Park and on over Wilkerson Pass into South Park.
Or, if you're interested in something truly unique, take Colorado 67 south to Colorado 165, and then south on 165 to Bishop Castle. Bishop Castle may look like a castlethat is to say, a buildingbut it's really a 160-foot-tall work of artofficially. It doesn't conform to any building codes but Jim Bishop won the legal battle that ruled his creation art, and therefore not subject to building codes. It's much too hard to describe it; you've got to see it for yourself.
In Colorado Springs you will definitely want to stop at the Garden of the Gods. This always free attraction features red rock slabs tipped on their side, soaring to the sky. Be sure to drop a contribution in the box to help pay for upkeep.