We are renting an RV in Phoenix for 9 days at the end of August. Our current itinerary is as follows: Sedona (1 night) Grand Canyon-South Rim (2 nights) Bryce Canyon (2 nights) Zion (2 nights) ...
I would recommend Bonita campground at Sunset Crater as well, then instead of South Rim , head up to the North Rim on your way to Bryce and Zion. It is cooler, 1000 feet higher, and not as busy as the South Rim. I have stayed at Kaibab Camper Village at Jacob lake. Has full hookups and is an easy, beautiful 45 Min. drive to the Canyon. Also, the drive to Jacob Lake will take you over Marble Canyon an by the Vermilion Cliffs-a lot of great views and wide open spaces.