Have to really, really recommend the Strataca Salt Mine and Museum in Hutchinson, KS. We did the full tour, all the things. I thought it would be lame, but I was really impressed with it. There’s a Dirty Jobs with Mike Rowe episode about it, though I haven’t seen it. (He has a life size cardboard cutout, though, of himself there!)
It isn’t claustrophobic in the least. I thought it might be, but not at all. One of the best tours I’ve ever done!
If anyone is interested in picture or more detail, him me up with a PM and I’ll provide a link to a Facebook post about it. (Don’t want to put external links in this post, just in case “the rules”.)