I would have to respectfully disagree with willdad2 and oscarsnellman. While it isn't a necessarily inepxensive endeavor, it is something that I would say is a rare opportunity and worh the money. Adults are $20 and kids 13 and under (check the web site for the exact ages are $10.95. The tour is guided and lasts about 1 hour. I would say that if you are claustrophobic, or don't like closed in places that you cannot get out of quickly, this probably isn't the place for you. The tour begins with a quick elevator ride down 260 feet the the start of the tour. A guide then walks you back into the mountain over 2000 ft where you ultimately arrive at the falls. The lights and sound that willdad 2 mentions do greet you, but I did not find it overwhelming and even if there was not theatrical music, the other people in your tour group would be making noise, so I don't see how the experience would be that serene to begin with?
Anyway, I think it was worth it, my family and I decided on a whim to go and it was easy to access off the intersate and not very far. On this trip, we were in our car, but if you are in an RV of any size you would need to use caution. If you are towing a trailer of any size I would be very careful and consider maybe not trying to stop while towing. The grade is pretty extreme >10% I would say and a there are a couple almost hairpin turns. I would call Ruby Falls for their recommendations.
This is a great place to visit if you have a spare 1.5 to 2 hours. When planning your trip, you can park directly at the visitor center or you can park at the Lynchburg, TN. town square and walk down Main Street about 1/4 mile or less, crossing a small foot bridge which brings you directly to the entrance.
Upon entering the visitor center there is a great history of Jack Daniels himself via several chronological displays within the lobby. Tours run every 15 to 30 minutes depending on how busy they are and are free of charge. The tour starts out with a short film, givnig a brief history and then takes you outside for a quick 2 minute bus ride up the hill to the Rickyard.
It is at the Rickyard where you exit the bus and the real tour begins. A guide takes each tour group (about 20 people) through the facility including the original office, the Hollow or spring where Jack Daniels gets their iron free water supply and the rest of the plant. The tour is family friendly and really very interesting. I would definitely recoomend it. No Jack Daniels is given out (Moore County is a dry county) but you can purchase commerative bottles on site that happn to have Jack Daniels Tennessee Whiskey in them. ;)