We bought a 86 and all of the above applies.
Many are "kits" and the definition of good condition (if stated) varies a great deal.
Rotten floors are very common along with cracked and poorly repaired frames (rusted out too depending on where it has been).
do major damage and even though it is a fiberglass shell the many penetrations give lots of opportunities for leaks
If it smells musty and you see mildew and mold then the moisture level is high enough for the wood to rot if any water collects. Some of the smell is the rot in the wood.
If the trailer has not been renovated then I would plan on doing it.
Take an ice pick with you to probe the floors in the back and front and "corners. Where the vents are located for the refrigerator
will let in water as well.
New flooring often hides the rotten floor.
The entire shell is supported only where the frame passes under it in four places.If the shell is sitting on the frame and shows signs of "mashing in" then the integrity of the floor is in serious question.
I am not saying you shouldn't buy the trailer, but rather know what you are getting into and how long and how much money it will absorb.
Many here are in the process of renovating their Scamps for this very reason.
The one I bought only needed a floor, frame repair, and everything inside.
I turned my "project" into a project to upgrade the whole thing and make it the way we wanted one. The guiding light
was what "She Who Must Be Obeyed" wanted.
Good quiet A/C, good floors, twin beds, no oven or gas burners, good sink, bath and shower you can stand up in, etc.
The cost of the trailer is the smaller chunk of money compared to the rest of the project.
Here is a link to some of my posted pictures on my project: