Take HWY 550 (N) out of Durango up to Montrose then HWY 50(N) to Grand Junction
I-70(W) to Route 139(N) to HWY 40 at Dinosaur CO.
Then HWY 40(W) to Vernal and then HWY 191(N) to HWY 189(N) in WY and on to Jackson
We just made this exact route in reverse: Jackson to Durango with one small variation (We stopped at Manila, Utah for our Flaming Gorge visit.)
This was our first time to tow over US 550 from Ouray, through Silverton, to Durango. We enjoyed it greatly. Wish we had not been so hesitant before. Our rig is a 34' fifth-wheel pulled by a Chevrolet Silverado diesel, Duramax/Allison. We never had a moment of concern about the highway or control of our rig. I highly recommend this route.
Our overnight stops between Colter Bay and Durango were Flaming Gorge/Manila KOA, Rifle Gap State Park, and Ridgeway State Park in the Pa-Co-Chu-Puk campground