Hwy 550

491 from Gallup to Shiprock is ok, at which point if you are going to 550 you head east on 64 to Farmington and get on 516 which pretty much ends at 550 take that into Durango then 160 east to Bayfield about 18 miles. 550 in that stretch is not overly wide and a bit hilly in areas but nothing significant.

Take 491 from Gallup up to Cortez decent road depends on your idea of scenic though then hit 160 east to Bayfield 160 is good road