I'm glad I found this site and this thread.  I am planning on doing exactly this, and would be cool to have company.  My tentative plan is to start around July 10 in Denver, finish before July 24 in Durango (although I have no idea how far I should expect to go in a day).  It seems like renting a car in Durango and returning it in Denver is the most convenient way to shuttle back.  I'd like to travel light and stop in any towns along the way to fuel up as much as possible.  Rather than miles, I usually look at elevation gain to assess difficulty, so I would stick to about 8000 ft gain per day.  So Wild, stumpy, and Brian, if any or all of you want to coordinate for riding together or logistics send me a pm.