I question the legitimacy of Cochise County's regulations in this regard. The issue is quite clearly NOT about health and safety.
This county, like most in AZ, is flooded with RV parks. The taxes and fees collected by the Country from these businesses are probably substantial.
My guess, opinion, whatever, for what it's worth, is that the County zoning regs vis-a-vis parking more than a certain number of RVs on private property are in place to protect that income.