From Mesa Verde take 145/62/550 to Montrose - a beautiful, easy drive with your motorhome. From Montrose take Hwy 50 over to Salida - no issues. We've driven those roads often with our 40' MH. Have a good trip!
Also, if staying in Montrose it would be worth your while to take your car down 550 south to Silverton. It's a unique little, fun mining town. This part of 550 is where you may have heard of a 'scary' road. It's just fine with your car. We've also driven it from Durango many times with our motorhome. (We enjoy mountain driving). We've spent many summers 4-wheeling in the southwestern area of Colorado.
Full-timed for 16 Years . . .
Traveled 8 yr in a 2004 Newmar Dutch Star 40' Diesel
& 8 yr in a 33' Travel Supreme 5th wheel