what I did
On a few installs I did...all 22' or less. On the 22 Cloud I put the Fantastic in the back. I draws air thru the entire length that way...including the galley and toilet areas. The front is either another Fantastic or a crank up vent. The center is for the AC. It just works better there. On the Cloud I had to run electric wires...time consuming but easy to pick up 12v
from the lights. Your Airstream may have wiring waiting for you in the ceiling...check with someone in the know...ie., Andy at Inland. Definitely run a drain line from the AC....easy to fish it inside the skin while you have the 14 x 14 AC opening available... to the side where you can come out in the closet or cabinet for a run down to the outside thru the floor. Don't have it drain on the side by the door where you will have a mess where you will probably set up outside activities.
"If it can't be reduced, reused, repaired, rebuilt, refurbished, refinished, resold, recycled or composted
then it should be restricted, redesigned or removed from production."