What an amazing collection Rick, I had no idea the breadth of products involved, over so many manufacturers. What a lot of looking and buying over many years to build this up. Would be a bummer to split it up, but that’s life. I really hope you find a buyer who understands the value and rarity of many of those pieces.
You might consider getting a professional evaluation from, say, Trainz, Stout, or AmbroseBauer, etc. There’s a chance that one of them is aware of a wealthy buyer or two who’d be interested in the whole shebang, intact. Or at least that’s what I’m wishing for you!