I know nothing about the operation and setup at Robbers Cave, other than some short mentions in the papers when they started up. Around 1886 or thereabouts, there was a brewery on the site, but I think they just stored beer down in the cave. There were remnants of the original buildings there in the late 60's and the last time I was in the cave was 1972. The previous owners used to rent it out for wedding receptions, parties, etc. and I was there for a party in the wee hours. It's all sandstone that was carved out mostly by subterranean water with some help from people who apparently had nothing better to do than whittle away at the walls. There's a local legend that some bank robbers hid out in the cave at one time while running from the long arm of the law... hence the name. I have no idea how much truth is in the story. I know that the year I went into the service, 1973, they closed it down because local law enforcement was not keen on all the booze/pot at the parties and there was some question about the stability of the cave. It seems to me that a small part of it collapsed, near the "back exit" and they filled that entrance in. It opened back up some time in the 1980's and you could pay $5 to tour it. When the brewery leased it (I think from an LLC that formed to purchase the property) they had to dig that old entrance back out so they could have an emergency exit (required for all things open to the public, in modern times) and I guess it was about 30 feet of dirt and rubble that had to be dug out of there. They were putting in more modern staircases and ladders and lights and shit the last time I saw anything about it, a couple of years back.
As teenagers, we used to sneak into the cave through that back entrance, since they kept the main one locked up. That one had a little wooden shack thing around it. I believe the investors still plan to open it back up to the public, some day. I hope they intend to improve the ventilation. I remember that it reeked of piss and beer and raccoon shit.
It really was a rather cool, winding cave... but small and boring compared to places with big caves that are in real rock. Nebraska isn't exactly famous for having caves. We also used to sneak into the Ogallala Water Aquifer before they closed up the entrances with concrete. That was about a 100 foot descent on rope from the surface. It was huge, cavernous, and very dangerous. Water was very cold, and the level could rise enough in an hour to drown anyone on the sandstone "land" parts, which happened a few times. Mostly drunk teenagers. I know one teenage girl died when she fell on the descent. It was very much against the law to enter the aquifer, and the authorities pressured the land owners at the entry points to seal off the holes after that incident. I don't think there's any way down into it, anymore, that is accessible to drunks and teenagers.
I'm sure there must be much better caves and perilous adventures in Ohio. I mean, you've got to be disposing of the bodies somewhere.... other than behind dumpsters in the back alleys of Columbus.