I remember when I was a youngster in the 70's they were building the Champion / Titian and Concord motor homes in a plant in my home town in Canastota, NY . Can't help you much on how they were built that you don't already know , /wood frame with aluminum skin . I remember hundreds of the in the yard ready for shipping . haven't seen one in some time . Good luck on the project .Sounds like a adventure ..