I like the title, it seems like a possible Neverending thread. I have my share of fixer uppers. Most need weights and better couplers.
My last batch from FBM included some Varneys. They seem pretty good. Body mounted draft boxes on the bodies. Trucks that are attached with screws instead plastic push pins. I'll continue to watch for their stuff.
Those other things with truck mounted couplers and horn hooks, I'll just leave them as is from now on and make one horn hook and one kadie car and run them. My experience with upgrading them is terrible. The trucks bump into the draft boxes after converting them. By the time do i a full upgrade, I may as well have bought something better.