Both 26 and 40 are very scenic with some pretty steep grades and curves but nothing to really fret about if you take your time and drive sensibly. Save your brakes by using lower gears. Stay in right lanes and let the fast traffic go by. Although some of the grades are steep they don't last as long as the Rockies and all Interstates are drivable with your gasser. Just don't be in a hurry. I've driven these two routes in cars, a Class B, pulling a big Montana 5ver, and a MH gasser. You will see every type of vehicle using these two routes. I would stay on the Interstates thru the mountains. Some of the local roads can be much worse.
