welcome to the forum. We just came back from Washington State, where we picked up our "new to us" 1963
Overlander. Seems we'll be sharing lots of the same questions.
Ours is more of a "Overlander Kit", beinf that it is mostly an empty shell.
Anyways, I suggest you take a real close look everywhere, especially the floor. My floor is severely rottet out under the bathroom area, and under the front window.
I can't even really call it a floor.....toothpicks is more llike it.
A restoration project on an old Airstream pivots on the floor and frame, in my opinion.
So, I would do some severe investigating, and then make a plan.
I suggest searching the threads for keywords like " separation", floor replacement", frame repair, etc.
Most of it has already been discussed on the forums.
If teh Asbestod tile is solid and sound, you might be able to apply a flooring material over it. Otherwise, I would remove it ( wear respirator) before installing new flooring.
Defective flooring sections shoul dbe cut out and replaced, if possible, to prevent the rot from spreading further. Many have also used a product called Rot Doctor.