We did the same as you are planning to do several years ago. We used an outfit called RV Super Storage.
http://www.rvsuperstorage.com/
Their facility is located just south of Phoenix in Chandler. The owners also had a deal with a local limo driver whom will pick you up and take you to the airport. I think the cost was about $35 plus tip. He will also be there for your return if needed.
The facility is new and has several types of storage available, covered, inside, and outside.
A little tip: make sure you have plenty of water in the toilet bowel as it is so dry down there it will evaporate quickly. I had to rebuild mine and install a new gasket/seal after I picked it up. Mine was stored in March and April
I would use these folks again and recommend them to fellow MOC'ers.
Jim