Welcome, Barry and Kathy!
Here's a link to an inspection checklist you may find useful:
Fiberglass RV - Document Center - Buyers Check List
All really old trailers are subject to
frame failure and
floor rot.
Trilliums are most vulnerable to frame failure toward the front where the frame curves upward as it comes out from under the shell. Some years (???) were especially vulnerable and were recalled for frame reinforcement.
Scamp 16 failures most often happen at the front where the frame curves into the tongue (typically on the street side).
The
Scamp floor is plain wood (plywood on older models) treated with
fiberglass resin. Floor rot usually comes from neglected
leaks in
windows, vents, and plumbing. You'll want to take a flashlight and screwdriver and poke around inside, giving special attention inside benches and cabinets around the perimeter of the trailer.
Floor rot is not as common on Trilliums because the floor is encased in
fiberglass above and below, but it can happen, and it's a real bear to repair because of the
fiberglass. You'll have to feel for soft/spongy spots.
When you're inspecting the shell, note the difference between "spider cracks," superficial cracking of the outer gelcoat (common, but not a cause for concern) and
stress fractures, which go all the way through the fiberglass and require repair. The latter are most common at the corners of doors and
windows.
With Scamps,
door fit is another potential problem area. If the door is sagging in the opening, it could just mean worn-out hinges (which are still available from Scamp) or it could mean structural problems with the shell-frame attachment around the door. A gap at the bottom of the door could mean a bulging shell caused by a loss of interior support or that the wood stiffening material inside the door has become wet at some point and swelled, causing the door to lose its shape.
Most molded fiberglass trailers use a
rubber torsion axle, which has a useful lifespan of 15-20 years. Since both of these trailers are well beyond that, it's something to ask about.
All the rest is pretty much standard RV stuff to inspect and test:
electrical, plumbing, appliances,
tires,…
Hope all that doesn't scare you off! If you have a smart phone, you might want to install the FiberglassRV app and take it with you when you go to inspect. You can take a picture and post directly to the forum, so if you see something of concern, you might be able to get some real-time feedback.
Best wishes in your "egg hunt"!