As with a boat, plan on a break in period. I would lean towards florida if you can live on the boat for the first couple weeks while you get the motorhome sorted out and do a couple trial runs (if you find time consuming issue, you can live on the boat while the repair shop fixes it). Plus rather than buying all new stuff or shipping it across country, you can simply move it from the boat to the RV (bedding, cooking supplies, clothes, tools, etc...), at least that's what we always did when switching back and forth.
Are you planning to pull a car behind the MH? Unless you go really small, it's a pain to pack everything up when just going out for a day trip in the MH. Once you add the cost and complexity of pulling a car, look into picking up a similar size travel trailer or 5th wheel and truck as an alternative.
Arizona isn't a bad place to look but assuming a small to medium size Class C, it's not really a prime area (yes, you can find them). Snowbirds tend toward big units as they aren't moving a lot. Now if you are looking for a monster 5er and 1ton dually or a big diesel pusher MH, then it's a prime place to look.
I doubt you will save enough to worry about east coast vs west coast pricing.
