Hello Jeff,
As said, there is no magic age. I found my 1999 13' in East Tawas, and I helped facilitate a sale of a 2013 16' Scamp in Lapeer, so they are around occasionally. Best you can do is put out what, specifically, you are looking for, and someone might see it and be able to point you towards a possibility. That's what happened with the one I facilitated, it wasn't even listed
for sale, but the owner had mentioned to me that he may be interested in selling in a few months. I just gave the owner the number of the folks looking to buy, if he was interested. He was, and all were happy, the sale was made.
Anyway. If a trailer looks good and the floor/frame is sound, most other things can either be addressed by an RV repair facility or other Trailer Service company. I did have the
axle replaced on mine, and some
electrical problems resolved, I now have a trailer that I anticipate will be going long after I'm done with it. Of course an older trailer may need more cosmetic attention, but structurally they are fairly simple. The major projects that could come up would be needing to reseal the
windows eventually, though I have no
leaks in my 1999 Scamp.
Also, keep in mind that you are relatively close to Backus (a one day drive) so you COULD take it there for any attention a used trailer needed. Just add a stop there on a vacation trip - that's what I did to have a Fantastic Vent installed in mine. Their service department has been very accommodating and did good work quickly. Not exorbitantly costly, either.
Good luck with your search.