Either of the routs mentioned to Montrose are stunning---albeit quite different. Jamawani correctly points out the cool Silverton-Durango railroad which cane taken to get to Silverton and then grab the Million dollar H-Way there---US550---the climb up to the top of Red Mountain (between Silverton and the next town Ouray is not bad) and then an awesome descent down to Ouray---where thankfully you are on the inside of the road----plenty of photo ops on this road.

Alternatively, the road from dolores to Telluride over Lizard Head Pass is also tremendous---much less traveled than US550. Awesome scenario and light gradients to the top of Lizard Head and a nice descent into Telluride. From there a bit of work over Dallas Divide to get back to US550.

Enjoy this area and what might be the most scenic of al of Colorado, especially to take in on a bicycle, IMO. safe travels.