Welcome, Mike. Boy, are you brave! In some ways, an Airstream isn't any different than any other trailer, while in other ways it is a completely different animal. For starters, how are your riveting skills? How familiar are you with working with aluminum? Airstreams are nearly all metal.
The one area where there is wood is the floor. Any area under/near a door, window, or roof opening is a place where there can be water damage.
You realize that you are looking at a trailer that was built nearly 50 years ago, so you can expect that there are lots of places where there might be problems. Also, someone has started working on it, and it may well be that the real reason they are selling it is that they got in over their heads. You are looking at a project that will take several years to get ready for use. Is that what you want?
David Lininger, kb0zke
Heartland mpg 181 (sold)
1993 Foretravel U300 (for sale)