We like the area east of Phoenix, the Mesa, Apache Junction, Gold Canyon, etc area. We've been snowbirding for about 17 years now and noticed a real decline in visitors about 10 years ago. It has seemed to pick up since then, to the point that we can hardly get RV spot reservations in the nicer parks. They are all pushing park models, of course, and RV spots are getting squeezed out.
I think the higher fuel prices and economy collapse around 6 years ago froze new RV park development. I suspect new parks will begin to pop up soon. One or two companies control all of the RV parks east of Phoenix and have a captive market. Hopefully, some new investors will tear up that playground.
More on topic; I used to feel that RVing might die out, but now suspect that it will come back big time if we change politicians and get our economy moving again.