Possible, would have needed to get 318 from D&RGW as K-27's weren't allowed south of Ridgway. But consider getting the line to Dallas Divide also. Only one major bridge (9A at Pleasant Valley) & all in Ouray county so no political problem with the anti RGS folks in Telluride (ca 1951). Well away from the hiway too.
As to bridges, that's one of the reasons I'd have gone for Durango-Dolores. Only 6 major bridges on that section (103A at Dolores, 125B at Menefee, 128A, 131A at East Mancos, 146A at Hesperus, 160A Lightner Creek)
Oh and the D&RGW bridge over the Animas. Only 125B was a real problem child as far as I can tell.
hank