Well as you can tell camper restoration is a labor of love. The only reason to do it is because you want what you want, not what is available.
As far as construction methods, you are competing with a rather low bar.
The first decision is do I want to fix up and old camper, what I call patch and go. Or, do I want to build a first class unit that will last a long time.It seems to me the previous owner made that decision by gutting the camper. However that owner decided to cut his losses and sell it.
If you can get or figure out the original floor plan, you will know why things are where then are. Furnaces, water heaters, refrigerator, vent pipes, black and gray pipes, range hoods are some of the things that pierce walls, the roof or the floor. This my help you decide how you want to lay out your floor plan.
As a said it is a labor of love, it is not cheap nor will you recoup your investment. If the fame to box connection is solid and you have no leaks, you are off to a good start.
Good luck
