We have owned our gv now for 4 years and have always wondered what the monocoque chassis was made of(aluminum, steel?) and whether anybody had ever had structural problems. We had to replace the framework under watertanks due to corrosion as watertanks were seriously sagging. Are monocoque chassis any better than conventional chassis?
The monocoque chassis is one of the best in the world. Think of it as a unibody-- virtually all vehicles have gone with it. Prevost uses it, MCI used it, etc. Basically the whole structure is used to strengthen resistance to twist, not just two frame rails.
Your Foretravel uses steel in the structure-- finding beams is easy with a magnet.
And as far as issues, be sure you have read: Bulkhead Repair-- A Comprehensive Look REVISED (http://www.foreforums.com/index.php?topic=8645.0)
One exception: the roof structure is aluminum. I have the same year/model/floorplan. On cold morinings you may notice the two hall doors get tight at the top when closed. Aluminum shrinks more than steel with temperature drop.