We found that there are several caverns in the area of Luray, VA that are open for tours to the public.  We went to two of them, Luray itself which is the best-known, and Endless Caverns which is on the site of the RV Park where we stayed.  This is a cavern and we were the only two people on the tour we took.  That is actually a good thing, we were able to progress at our pace and not stop and wait for slow-pokes like you have to do on a tour with 20+ people!

We were impressed with this cavern; the formations were wonderful here as well!

Here are pictures we took: