A trailer in that condition would not be worth a whole lot in my book - it will time a lot of time and effort to make it useable. So I would think the decision is do I have more time or money - if you have more time, buy it for next to nothing and work on it as you can. If you have a bit more money, wait and find a better unit that does not need so much. I think your ahead of the game (time and money) and spend a little for a better unit and go from there.
1956 Flying Cloud
Four Corners Unit
Albuquerque National Balloon Fiesta
Vintage Trailer Academy - Formerly the original