A few things:
The owner of 213 doesn't seem to be a serious seller. If he's only taking queries via a third party, it makes me wonder if he's even got email. This IS South Dakota we're talking about. Phone calls and in person conversations are far more common than emails in that part of the world. If he really wanted to part with it, he would have made a deal years ago. It's not like no one has tried to buy it off him. If he was gun-ho about getting cash from it, he would have scrapped it ages ago (along with some of the other actual junk he's got laying around - that DD40 shell is worthless, and no one even mentions the rotted out SOO Gp30 shell in the same dead line...).
Unless 213 is laden with asbestos, it's either going to be scrapped or moved to another location, where it will sit until the owner passes away. Asbestos in this situation is good, as I'd imagine that disqualifies quite a few scrappers from wanting to go near it. It reminds me a little of those D&H shark noses: assuming they're in that shed, no one will see them until the owner passes.
Different topic: A lot of the recent cars and cabooses that went to scrap were pretty beat up. None left the island on their own wheels. If an org is struggling to find cash to preserve what it has, another rusting out, floor-less baggage car or a caboose with a smashed end stairway isn't going to help the cause. LIRR staff seem a little odd about donating equipment too. I tried to get a caboose for a legit display in Queens, and those conversations were cut off randomly. (I'm not quite sure why though I suspect a not-too-smart person not connected to rail preservation also in talks with the MTA threw a wrench in the works).
That B&M alcohol spray car has a great story. Definitely worth the effort no matter what color it's restored to. It's paint, it could be changed later if need be... (oh wait that takes funding... cash... volunteers... all not easy to come by).
The 211 or 221 would be potentially easier to get and certainly closer to transport. Even if they don't run they'd make a good display. The mere fact that these both exist and would be cheaper to transport that 213 *should* be something its owner considers if trying to sell it to underfunded groups on this side of the country, but like I said, I don't think he's a serious seller.
I forget the details offhand but at least one of the C420s in mexico seemed to just be rusting away at a museum there. I can't imagine it ever getting back to the states but I wonder if anyone has ever reached out to get some info on it's current state, and if some sort of support could be used to maintain it in place. I doubt many buffs would be interested in making a trip just to see it, but who knows where collaboration between like minded people could go long term.