Well, you can get a little info here, but it is pretty sketchy. I'm not sure if travel trailer mfrs have (or adhere to) a rigid spec as car manufacturers do. By the way, my TM's VIN came up with an invalid check digit in the 9th place. I simply substituted other digits until I found one that was valid. Still didn't tell me much.
I haven't found a really good VIN decoder for travel trailers.
http://www.analogx.com/contents/vinview.htm
Bill