I just bought an 86 Sovereign
and was a novice when I bought it. Here are a few points that I learned.
1. Check the flooring using an ice pick or large nail. The places most prevelent to damage are at each end of the Airstream. Lift up the bed and check along the rear wall for rot. Water was getting into mine from the rear bumper and running inside. I had to replace the whole bedroom floor. If only I had used a nail to check. Likewise under the sofa along the front wall. Another spot is near the door on each side. Sometimes there are leaks around the door. When the floor gets wet, it swells up and will turn black with rot.
2. Check all walls near windows for water stains or any eveidence of water leaks.
3. Make sure that the unit is connected to water and test the water pumps and water heater. Check under the counter for leaks.
4. Test the propane system, especially the furnace by leaving it on for a while. Mine would light, then go out and the regulator and motherboard for the furnace had to be replaced. My stove was okay but the oven that had never been used did not control temperature.
5. Get a ladder and physically check the condition of the top for condition of clearcoat and dents. Also check the airconditioner cover for cracks and cleanliness.
6. Check the tires to see if the tread wear is even. If the trailer has hit a curb, the wheel alignment may have gone out and you will see uneven tire wear.
7. Check the overall condition of the clearcoat very thoroughly.
These are just a few things that cost me a bundle.
Good luck. They are really nice when redone with new carpet and curtains.