There are any number of storage facilities in the Phoenix area. I'm more familiar with the East Valley (Mesa-Gilbert-Chandler) area. I would not be comfortable leaving a nice RV in uncovered storage in downtown Phoenix or near the airport.
The location described above on the West side looks very good, especially if you are looking for indoor secure storage.
SuperShuttle is a very efficient way of getting to the airport -- 20-40 dollars, readily available, and very dependable. We use them from Mesa all the time.
