Sorry, I would never buy a trailer, sight unseen, even from me. And I have sold at least one to someone, sight unseen by them. I never heard from them again. Happy or mad, who knows?
Even the volunteer "local inspection" which is available on the Forums has the drawback of quality of the inspector, and what they see, that does not bother them, but would bother you. Or what they don't see that you pick up on and they don't.
On the other hand, if you really know very little about what you are looking at, or much about Airstreams, you can fall into a money pit of issues even after you inspect it, are happy, and buy it.
I don't think there is any magic solution to the question. I only know that buying a 1955
Airstream, sight unseen, would not be something I would want to do.