Arizona is large and diverse state - from below sea level to well over 10,000 feet.
I will presume you want to be warm so that brings you down to lower elevations. That being said, it is already mid Sept and you best make a decision soon as many places are filling up, if not already full.
Many are 55+ age.
What are your interests? Like huge,congested city? Opt for Phoenix. Like warm with not much to do outside the RV park? Opt for Yuma. Want a great place? Opt for Tucson - which is why we moved there 12 years ago! Big enuf but so much to do.
Hey, we came there from MN -- with an 8 year stint in Estes Park in between.
Lots of places in AZ.