Coincidently, the wife and I have a son and daughter-in law who also reside in Denver and have visited them from British Columbia a number of times while pulling a travel trailer. We always hit various locations en route, mainly for photography. Not sure of your intended set-up and whether you will be pulling a smaller vehicle with you, so I offer this:
Some/most of the locations you suggest require vehicular travel from an RV site so be prepared to either unhook your RV or have a second vehicle handy.
Although possible, not sure you could comfortably do all the locations you anticipate (unless you do some long driving or only spend a very short time at each location).
A good first stop would be Moab, Utah. I would drive highway 128, just west of Grand Junction. It is a very pretty drive along a secondary highway and alongside a river. It arrives just outside of the town of Moab. There are a few RV places in and around town. Arches is only minutes from Moab, while CanyonLands/Islands in the Sky entrance is a good half hour and the photo view points are another half hour, forty minutes farther, depending on your driving speed (I did sunrise at Mesa Arch and had to travel in the dark at about 10 mph to miss hitting the gazillion rabbits and deers running across the road). You can find camping in various locations within Canyonlands, however, but again, you are packing up and leaving to get to Arches.
Be aware that some areas within the parks are over-run with the most annoying flying insects (not sure if they are gnats or mosquitoes or whatever but boy can they be a pain at certain times of the year as soon as the sun comes up). As I have not camped within the park, I am not sure how bothersome they are to campers but they drove us crazy.
A good second stop might be Monument Valley, which is south of Moab. There is an RV place right across the highway (Gouldings). If you have the chance, drive some of the interior road. It is sand/gravel and easy to drive if careful. Not sure I would take an RV though. There are guided tours available as well and they supply transport, for a price. Regardless, visiting the main viewpoint is a must. It's from there you can get the iconic Monument Valley photo. Hotel/restaurant and gift-shop are located at this viewpoint.
Others will probably offer more/better info.