[twindman]

I'd suggest going to a local park and camping for the weekend. Gives you a safe way to begin. Also, we bought our latest (current) rig in July in PHX. It supposedly had better insulation, etc than our 2006 previous model.
Went to park around 4 pm. Temps were around 115 or so. Turned on air and went to supper. Home about 7 pm. I think inside was still 95-100. Went to a movie and came back at 10 pm. Temp was WAY down to 85! lol.
Went swimming until 11 or so and still at 80+. Pulled out hide-a-bed in LR, opened the down vents in the AC and slept right under the AC. Finally around 2 am I had to put a sheet over me.
That was all I needed. I ordered a BR AC and had it installed in 5-6 days and then after a couple more we took off for 3 months to the annual Rally in Goshen. Then on the way I noticed 2 slides opening about 3 inches after 200 miles or so. Kept putting them back ever few hours on the way. took to Lippert in Goshen after the rally and they didn't even test - just installed 2 new cylinders. On the way around noon that day.
Sooo, a short trip may teach you what you need to add, etc and be a learning experience. OH, if you plan on seeing AZ a lot this summer, I strongly recommend a BR A/C unit. One AC takes a long time to cool off the rig when traveling all day.
Good luck.