I'm trying to think of ones that haven't already been mentioned. Comet MT is one.Pony which I hit last year is a living ghost town.Hughesville? had some serious ruins but one of the websites say much of it has been demolished. Bannack if you can only visit one in MT. the only one I've seen more extensive than Bannack is Bodie in CA > it's also a State Park which seem to help in preservation. Some government agency's are only allowed to stabilize buildings. Some allow volunteer groups to come in and restore bits to what is supposedly looked like in the day.