Substitute the CO Natl Monument for Arches in Busskipper's itinerary, and you have a good plan! :)
I would suggest adding the following short drive to see more sandstone from the air-conditioned interior of your vehicle. Heading west from Ridgway on 62, you start with views of mountain peaks. After cresting the Dallas Divide you descend steadily. Take 145 west and continue descent into the varying sandstone strata. 145 crosses the San Miguel River and then climbs sharply, again showing the different layers of sandstone with their differing colors, until the highway tops out on a verdant farmland plateau near Norwood. There you could turn back or, if you wish to make it a circle tour, you could take 141 north (it goes almost to Grand Junction), then return to Ridgway on 50 & 550. Or a longer circle tour variant would be to continue west on 90 (which becomes Utah 46) to US191 north into Moab, then scenic hwy 128 to the expressway which takes you back to Grand Junction. On this last route, there is a nice arch right along the side of US191 a few miles south of Moab, where you can climb around on the sandstone and take pictures.
I still want to get back to Ouray someday and take one of the Jeep tours over the Black Bear Pass, which descends on steep switchbacks into Telluride. The pass doesn't usually open up until mid-July due to snow.