There is a cave to explore at Great Basin, but we didn't find a lot of other things to do. I'd shave at least 2 days off and add them to the Capitol Reef area. There are some excellent 4WD trails in that area.
Have you been to Goosenecks? Unless there is some other park of the park that we missed that park is just an empty, bare rock space. With spectacular views of the Goosenecks but I don't think I'd want to camp multiple days there. There is a great deal to do in that area besides the list above there is the Canyon of the Ancients. I thought Monument Valley is pretty much ruined by the way the Navaho's have commercialized it. The scenery is still spectacular tho so it's worth a drive thru.
Oh yes a warning about Mesa Verde. Many of the tours can ONLY be reserved online and they fill up. We were in Cortez for a week exploring the area and never managed to get any of those tours. Long House and the self guided tour are still available inpark.
I'd suggest doing what we did. Staying in Cortez and using that as a base camp for Mesa Verde, all the four corners area like Hovenweep ect, and Monument Valley. We stayed at La Mesa RV Park which was quite nice but it doesn't have a lot of rv resort type items. We payed a weekly rate of $150. Since we are out all day long I don't care about swimming pools and such.
Oh yeah, Moki Dugway for sure.