An honest opinion on value is that everyone has their own opinion. Not sure how many were built but that one does look interesting and would be fun to travel in.
I would start with what it would be worth in restored condition and that would be the baseline. Now start to add up what it would take to get it there, it may take much more money to get it there than if you just go out and buy one done.
This does not take into account the experience and satisfaction of restoring it yourselves. Allot of satisfaction for being able to say "we did it" and there is no way to put a value on that.
Good luck in finding one of those in the $2,500.00 range, most of the restorers would snap it up for that.
here is another that I found;
1963 Airstream for sale in Fort Wayne Indiana - United States