Welcome... Learn the "Search" features..
Welcome to the Forum from Silicon Valley... The Search link on upper blue bar is hugely powerful for finding strings of messages on topic you're interested.. Among items you can search for:
1. Where to find an older Airstream.. Depending on how old, try RVTraderonline.com or Airstream.net classifieds (Vintage Airstream Club) or E-Bay or WBCCI "Blue Beret" Magazine for dealer or classified ads.. In addition, dealers have some, including Toscano in Los Banos and Manteca Trailers off SR 99 and 120.. (Manteca has 94 Soveriegn 22' for sale, and are asking more, but might take $12K...)
2. What to look for.. Search on "what to look for" or "problems with older.." lots of threads on frame up inspection processes, expensive problems (frame/wiring/refrigerators/plywood floors) etc etc...
3. Specifics on individual concerns: Refrigerators, A/C, Leaks, Plywood flooring, frame re-wlding, etc etc..
4. To save Big Dee the trouble, at least a dozen Airstreams of varying ages will be at Cassini Ranch campground at mouth of Russian River from Friday Apr 8th through Sunday, if you want to check out various vintages and talk to owners... Following weekend WBCCI Chapter will be camping at Pleasanton Fairgrounds... (That's official Wally Byam Club of Airstream Owners..)
In Theory, there's no difference between Theory and Practice, but in Practice, there is usually a difference...