We've used the Ridgway to Moab Road numerous times--all paved, 2-lane road with no problems with any size RV. Yes, there are grades--one from Utah border down into Paradox Valley that has lots of curves, one from Naturita up to the plateau where Norwood is located, another from north of Norwood down to the San Miguel River, and the long climb on 62 from Placerville up to Dallas Divide. None are difficult, just long, but you should use your lower gears on the downgrades and not depend just on your brakes.
As far as scenery, the Paradox Valley is dry and desolate, but it is also the location of the nation's first uranium mine (1898). The valley is a collapsed salt anticline (upward fold) with the center eroded out by Paradox Creek.
Naturita is slowly falling into ruin; people there have no hope of a tourist industry and hold out hope that Energy Fuels will build a new uranium mill there. Norwood is a farming town with great views of the San Juans and Lone Cone to the southeast and the LaSalles to the west. Be sure to stop just on the east side of Dallas Divide for some great photos of Mt. Sneffels and the San Juans (watch for a split rail fence on the right).
US 550 from Ridgway to Ouray is nearly flat as it follows the Uncompahgre River valley. As stated earlier, it's only immediately south of Ouray that 550 gets hairy--the Uncompahgre Gorge on the Million Dollar Highway. Use your toad for that!
You can take a real-time virtual trip over CO 90, 145, and 62 and US 550 using CDOT's OTIS website to actually get a windshield view of the entire route. I got you started with this link for CO 90: http://dtdapps.coloradodot.info/Otis/HighwayData#/ui/0/0/criteria/090A/0/33.874. Now you can really never say you didn't know what you are in for!
"Retirement is the best job I ever had!"
2015 RAM 2500 4x4 crewcab 6.7L CTD; 2016 Rockwood Signature UltraLite 5th wheel