Actually RVJim, answers or comments to the issues you raised are a good thing to post to the forum.
* Walls & stud spacing are never made available to us owners. I don't believe interior wall-stud materials are divulged. I think exterior walls
might be aluminum welded frame, though location is most likely a secret.
* Weight must be posted on a label affixed on a wall, likely behind the driver's seat or in a kitchen cabinet. Hopefully, you can trust the information. (Advertised tank capacities seem to be wrong.) I think most people stop at commercial truck scales to determine weights & distribution.
I'll let other members help with your additional questions. The sometimes non-existent / sometimes existent customer service (see
www.gulfstreamcoach.com) is the place to start for a CD. They were actually providing CDs for a while.