These coaches will not take a lift without SERIOUS modifications. Airstreams are "monocoque". The Body is as much of its strength as the frame. The frame droops without the body. Its built like an airplane and as a unit its very strong but separate its not. Lifts are major weight and they will put a major load on a small area of the coach and it just wont take it without a lot of work that may include replacing the frame with a heavy frame.
There is another Forum member thats is here that is working on the same problems. They go by Nevisstudio. http://www.airforums.com/forum...visstudio.html
Hit that link and you can read through their posts.
A couple things going for a Airstream over most coaches. They have a low entry hight. 18 inches in most cases on level ground.
They were working on a ramp. They also were talking about making the coach "Kneel" to lower the entry ways height. A single axle trailer this could be down quite easy with air bags. I would guess a stock coach could be made to lower about 8 inches with a custom suspension and a little smaller diameter tire like a 205 instead of a 225. Some modification to the inside fender well. Probably wouldn't be to much harder to make a twin axle do the same. Small air compressor off a Cadillac and the ride hight sensor so that it will maintain its normal ride hight while traveling.
Here is what would need to done to make it work.
Solid axle with a 4 inch drop.
Fabricate a link suspension using Air bags as springs on the lower control arms. Readily available parts. Pick up a low rider magazine next time your at the grocery store. Plenty of ads and you will probably find a few examples of suspensions like I am talking about.
So if you can loose 8 inches that reduces the ramp length needed significantly.
A couple other things that you will find is Rich has a few interesting ideas on how to make the bath accessible.
I have completely taken one of these apart and rebuilding it from the ground up. I honestly don't think it would be a huge problem to widen a door. A fabrication shop with a metal brake could widen a door pretty easy.
If I were you and handy I think your right. I would look for a fixer up coach with a solid floor, Rear bath and center twins is going to take the least effort to make it work. I think with that lay out it would allow you to move the wall for the bath forward to give some turn around room. Then shift everything forward if you have to have the twins or upgrade the Gaucho.
If you Scrap the twins in the rear you could move the wall forward to the wheel wells. Put dressed edge on the end of the tub to give her the room to back in front of it and slide over. Same with the toilet. Might have to relocate the water heater forward but with the twins gone there is not reason the water heater couldn't be located over the wheel wells. Then build in a storage cabinet over it.
Before shopping do some searching for "Rear end separation", "Rear end sag". Some of the 70's and early 80's coaches had some problems. Those posts will show what to look for and how it is repaired.
Here is a nice archive if you haven't already found this. http://www.vintageairstream.com/archives/index.html