I can't imagine being in the southwest part of the state and not doing the circle drive through the San Juans, Durango, Dolores, Telluride, Ouray, Silverton, and back to Durango. Maybe the best mountain scenery in the state. Bypassing the Million Dollar Highway between Ouray and Silverton would be a mistake.
I see you have a lot of desert and desert-like scenery, Sand dunes, Mesa Verde, Arches, but the mountain touring seems to be just what you pass through going to other sights. Pikes is worth a visit, true, but the view into the Grenadiers from Molas Pass is not to be missed!