I just joined this group so this may be old news. Comment on question #1: playing around with my dual a/c's ceiling vents, I noticed that both a/c's are ducted throughout the "house". That is, if you slide the ceiling vent selector to blow through the round louvered vents rather than straight down, each a/c unit blows through all the vents. Summers here hit triple digits & I can cool the house comfortably on either a/c unit individually, plugged into my home outlet, without popping the 15 amp CB. I try to park the rig in front of the house once a month over a weekend & I'll run each a/c for a day alternately to work them