Nice of you to do an inspection for your friend. Might save him a bunch of driving. The 65 model year was the last of the flat window glass trailers. At least a broken window is more easily repaired than the 66 to 68 trailers.
I recommend you print off the Airstream Inspection Checklist here on these forums.
http://www.airforums.com/forums/f138...ist-43294.html
I've used it a couple of times. It is just a systematic way of spending a couple hours checking the whole trailer. The seller ought to have the trailer "set up" for you with shore power and city water connected. The seller ought to do a full demonstration of every switch, appliance, and faucet. Basically, you and your friend will try to appraise the value of this trailer. My 66 Trade Wind had a good body, good windows, and reasonable condition cabinetry. I found out later the frame was good, whew. The rear floor was rotted, there was no working appliances, the plumbing was shot, same with the tires, brakes, and axles. I spent a lot of blood and treasure getting this old trailer "travel ready".
A fully renovated 65 Trade Wind is worth over $25k in my view.
David