Great, I'm planning dual alternators as well but possibly more lithium storage. For A/C I think 400Ah is more like 3-4 hours instead of 8 hours. It depends on the outside temperature though and running at night will take less energy. I'm looking at DC-based A/C units with variable motors so they aren't cycling all the time wasting energy. As far as EarthRoamer goes, I believe I read that they are using typical window units as most campers do in a box with a vent to the outside.