other Arizona suggestions
If you can shift your route a little east, two places I would not miss would be Sedona and the campground at Point of Rocks 20 miles west of Sedona in Prescott Valley. One of the most interesting RV campgrounds I have ever stayed in, tucked into fantastic rock formations with easily accessible trails that wind through a maze of small canyons, also a nearby lake. Great place for a day hike and the town of Prescott itself is a small charming place with a central square.
West of Quartzsite along I-10 are the Imperial Sand Dunes where you can ride dune buggies or just look at the fantastic sweep of landscape from there. Just past there is the Salton Sea, a fascinating place with a very nice State Park campground with $30 full hookups and spacious lots.
Farther south, Organ Pipe National Monument is one of the most amazing places I have visited in the Southwest. The campground doesn't have hookups but they have decent shower and bathroom facilities and the scenery is amazing, with the most dense collection of cacti imaginable and splendid vistas.