OP, a gas engine is good to about 36' and then a diesel for 38+. Not enough difference in MPG at 30' or 36' to worry about. Many smaller A's will have a 3500 lb hitch which will limit your choices for a toad while bigger ones usually have a 5K hitch.
I bought a used car from a dealer in Fla this past winter and he gave me a 30 day temp tag and no sales tax as I titled it in GA. I looked at the same car at a county auction and they stated that unless it was shipped out of state, sales tax would be charged. The above post about delivering to GA adds up but not sure why the difference. Had much the same on a MH I bought in AZ, but they delivered it to NM so I did not have to pay AZ sales tax.
For cold weather I'd put dual pane windows at the top of the list and then heated tanks. I would also want to know how to winterize as some are fairly easy (low point drains & hot water heater bypass valves) while others are not.