I know you say your budget does not run to buying new, nonetheless, I advise you journey to the NW Corner of NJ and visit Colonial Airstream. Just go to their website and you'll figure out why. They have a huge selection of new Airstreams and a reasonable number of newer trade-ins.
Take the time initially to figure out what layout and size make the best long term sense for you. It'll save you buying then upgrading 2 years later (and getting a name like "foiled again" because of it).
If you're determined to buy used, you could ask Colonial to give you a call when they get in a unit that meets your needs. Frankly you might want to increase your budget a bit for a newer one in better condition as it will be road ready instead of a basket case. Read a few "frame off" restoration threads and you'll get an idea of how many people spend $30K and over 2 years to get a vintage airstream road worthy and pretty!
Also there is an Airstream only park IN New Jerseyhttp://jerseyshorehaven.org/index.html
there are usually a few for sale in any park.
Happy hunting, Paula
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