Nuance: in the cities of Phoenix and Tucson, you must pass the
emission test to register. Details on
www.dmv.org .We went through this procedure in June 2018 with a 1995 Ford Tioga Montara motorhome. The registration process for a motorhome and a regular car in the United States is no different.
Arizona can also be the starting point of your journey. This is the state of the Grand Canyon, nearby Las Vegas and California with its numerous natural parks.
If you want to buy and register a car in another state, consult the DMV directly. It would be great if you could share information about your experience. In the future, I plan to make a review of all states about the possibility and conditions of car registration.