RV Parks around Moab and Kanab Utah

Can't help directly with RV parks as we stay at NPS or BLM CG's. But wouldn't advise using Kanab as a base to see Zion, Bryce, and Capitol Reef NPs. With typical delays at the tunnel, Zion will be 1 1/2 hours each way (3 hours every day), Bryce close to two hours (four hours of commuting), and Capitol Reef well over 3 hours each way (probably over seven hours of driving). I'd try to stay closer to each of these parks so you can see them rather than the windshield as you go to and from them. If you need FHU, try Ruby's near Bryce Canyon. Thousand Lakes and Wonderland seem to be used by some who need FHU nead Capitol Reef. Near Zion there are several options. Rather than me summarizing all of them, use the search feature and type in "Zion". You'll get lots of hits.

Unless you're also wanting to visit some of the NM's in the area of Flagstaff, might I suggest Trailer Village on the South Rim of the Grand Canyon. FHU CG convenient to the bus system around the village.