Las Vegas, Zion, Bryce (Ruby's Campground) the pick one of the many Natural Wonders National Parks, on to 4 corners (nothing there...really...you'll spend 15 minutes). If your into Westerns and Western/Indian heritage spend a day or two at Goulding's Monument Valley and take the tour through the Valley, Spectacular. Then North to Durango and Mesa Verde where you hike through the ancient Indian villages build into the cliff sides. Then either back south on the 25 to Gallup then drive through Petrified Forest to Williams and South Rim of the Grand Canyon and back to Vegas. DO NOT take the 550 North from Durango to pick up the 70. The 550, the Million Dollar Highway is listed as one of America's most dangerous highways. Great in a car, not great in an RV, even a small RV.
Happy Trails. Sounds like a great month.