That route Busskipper posted not only comes in as the best, but realistically the only route for most people with RVs. One could consider the Durango to Silverton and the Million Dollar Hwy but for those not accustomed to high country travel, twisty narrow roads with minimal shoulders and severe drop-offs, best to take the other route and not take the MDH in your RV.
Once in Ridgway, do take a toad or rental car on the MDH to see it. Stop at the water fall overlook for a couple pictures then head up further to see the old mining sites.
I love me some land yachting
