The plasticoat peeling, that everyone eventually endures, does not affect the usability of the trailer.
I elected to search for a 25' Airstream, 1980 something at about the $10K range, that had been cared for sufficiently to not show neglect, but reflected some pride of ownership in routine maintenence.
In April 2002, after about an 8 month search, I ended up purchasing a 31 Excella, 1984 in Lubbock TX, within the target price. It is a 2 owner, both prior owners had no children, and the interior was perfect.
The exterior has some peeling plasticoat from the years, and some light hail particularly on the rear end cap. But, the functionality of the trailer is not impared one bit.
With new Airstreams in the middle 5 digits in price, I thought the 31' 1984 Excella was a wonderful deal.
I have had to put tires on and a new water heater, but nothing else has been a problem other than riveting the belly pan with new rivets and shoulder washers to snug it up.
You can pay $40,000 up for a newer model, or pay about $10,000 for one in the shape mine is in and have just as much fun, and worry a lot less about the first signs of any peel of plasticoat.
Eventually, if I want it to look "restored", I will have to consider polishing it. However, because the used Airstream holds it's value so well after about the 10th year, if it has been cared for, I feel I could get my money back out at almost anytime.
Just my 2 cents....