Durango, CO to Grand Junction, CO without using Hwy 550?

550 isn't a problem if you forget the 35-50 and think more about the 15-35 MPH. Use the exhaust brake, keep the gears down to second, and ease it down in the really steep stuff, don't use the brakes except now and then to make the switchbacks. I towed down from Silverton with my 38FT HH weighing 16k pulled by my Chevy weighing in at 13k GVW, 29k combined and never warmed up the brakes. It's just all in how you do it, even had time to enjoy the scenery "some".