Wow, no cabinets, no wood interior, all guesswork for someone who hasn't done an amerigo
before. But a fun challenge!
We refurbished a 1973 amerigo in 2015-2016.
You can see some of my threads-- try searching under topics like: Kai, 1973 brown amerigo, Fear of Fiberglassing, etc.
Be aware the ceiling has molded-in areas specifically to place & secure your galley area, closet/fridge cabinet, and front niche (which was not manufactured as a bathroom, but as a closet); a great number of these had a toilet plumbed in, which was the weakest spot for rot to begin...we discovered our floor area in there as too small for anything but storage of several items including a porta-potti...not big enough to turn around in.
Depends on how you choose to build it, of course...but real estate is real estate. You even have all the logos outside!
Wow. Great price! Good luck with it!