By a "show cave," are you thinking "commercial," for this is a lava tube that's run by the FS, which this link will tell you all about it.
http://www.fs.fed.us/r6/centraloregon/n ... r-du.shtml Definitely has stairs, where some of our Howdy Party cavers were having some slip/sliding coming back up out of there, because it was raining like crazy and they had embibed more than they should have. Don't believe it was a commercial cave, but one run by the FS because of all the other lava tubes in the area; and, this is quite close to the highway going from Klamath Falls to Bend, and farther north. It's almost a straight shot for about a mile and for the most part, is quite safe, unless you twist your ankle--Aha!--or trip over your own two feet.