What to look for??
You don't mention the general era of the Airstream that you are seeking, and that may have some bearing on what should be on your check-out list. Regardless of the rig's age, you would want to be sure that all systems are properly operational - - especially the refrigerator (minimum replacement cost is usually over $1,200), air conditioner (minimum replacement cost is usually at least $650), water heater (minimum replacement cost is usually at least $500), and Univolt (minimum replacement cost is usually around $400). In addition if the the rig has exterior awnings, these should be demonstrated to be in proper operating condition as mechanical parts for some awnings found on Vintage Airstreams are very difficult to find. On units with rear hinged doors, you will want to be careful to check for evidence of poor fit resulting from the door being blown open in-transit - - this often results in poor fit and leak damage. Any trailer more than five or six years old should be carefully examined for evidence of floor damage resulting from leaks around the entire perimeter of the coach - - replacing rotted floor sections can become prohibitively expensive very quickly. It never hurts to check operation of all windows - - broken window mechanisms can become quite expensive to repair - - and on Vintage coaches the parts aren't always easy to find. If you are fond of the idea of a highly polished finish on your coach, the cost of polishing and re-plasticoating can become an issue - - the current cost of such professional service seems to be running between $145 and $175 per linear foot of trailer length including bumper and hitch.
Good luck with your search!
Kevin D. Allen
WBCCI (Lifetime Member)/VAC/Free Wheelers #6359
1964 Overlander International/1999 GMC K2500 Suburban (7400 VORTEC/4.11 Differentials)
1978 Argosy Minuet 6.0 Metre/1975 Cadillac Eldorado Convertible (8.2 Liter V8/2.70 Final Drive)