Thanks guys.
Pretty sure it is a clutch bit and I'll try both a little more force getting them in the hole and possibly file a few bits some to take just a little off of them to accommodate the smaller holes due to rust grime, etc.
I found a 1969 postcard from a CG in Silver Springs FL behind the mirror. It was already mailed and postmarked (with note about trip). I may try to find original sender and/or receiver and see if they are still available and would like to have it.
I have read quite a bit on a few sites dedicated to restoring vintage trailers and have learned that the interior walls and cabinets are an interpgral part of the structure, whatever I build back will do that too.
Yes, the PO (or one of them) had put a 2x4 spanning the rot you see in the pic and then held that up with the balusters.
Westend, wow, that was alot of work and very nice. I skimmed your post (but did not have time yet to read all 37pages) but will be bookmarking that and finish reading over the next couple days. Great project.