Hi gutzie from Minneapolis. Welcome to Air Forums and welcome to a big project. I think you will find these Forums invaluable research. Many Airstreamers have done what you are asking.
Your 67 Sovereign
is rather unique. It has the infamous Corning curved glass windows, but has many nice features. Maybe your is an International trim with very nice cabinetry and other amenities. The Sovereign
was the top of the line in 67. I like 60s Airstreams like I like 60s muscle cars, 60s popular music, and the 60s "revolution". It was an exciting time to be in college to say the least.
My 66 Trade Wind had rear floor rot, but the rear most rear cross member was still in good shape and the body still attached. See photos. Airstreams are built light using a semi-monocoque construction technique where the body, subfloor, and frame all depend on one another to keep things strong and light. So if one of the members rots out, things start to flop around. My 66 still needs work, but it is "on the road" and comfortable.
Of course your Sovereign can be repaired. It is much cheaper to do it yourself, or most of it yourself and hire a welder when needed. This repair will require welding. It is easier with the body off the frame, but it is possible to repair it with the body on the frame. Maybe your frame is not buckled behind the axles. Some of them are.
And then comes the costs. I would suggest you will have $15k and 1500
hours in your renovation project to get your Sovereign travel ready and looking nice. The more you subcontract, the more it will cost. Longer trailers like yours and mine are not worth as much as the single axle "cuties" like Caravels, Globetrotters and Safaris that are very popular. But the Sovereign would make a very comfortable traveler for long trips.
There are very knowledgeable Airstreamers in the Minneapolis area. Stay up all night tonight and read Minno's thread "Little Girl Refurb" or something like that. His is a 72 Sovereign if I recall correctly. It's a great thread with a great result. Find it an the Airstream Knowledgebase toward the bottom of the Forums page, then click on Sovereign, then 1972. I think you will find it there.
Better yet, here is the link:
So make a plan and get started. Rear end separation and repair will be just one of the major items on your list.