Festival of the West
I haven't been to the event you are talking about but, I go the the Festival of the West, just outside of Phoenix, every year. It's a great time, especially, if you're into the Western lifestyle.
This year, it's in March (19, 20, 21 & 22).
Google Festival of the West for more info.
There are tons of RV parks in the S/E part of the valley that you could park your RV.
I've been to Kanab, UT. many times & am aware of some of its film history. It's a beautiful part of the country. Try Houston's Trails End restaurant for very good, reasonably priced food in the center of town.
Joe F.