This cave system is one of the least expensive with lesser traffic going through in Virginia. Skyline Caverns is really close to Shenandoah National Park as well as other cave systems you can tour.
Skyline Caverns is located right off Stonewall Jackson Highway with plenty of parking.
The cave tour is about 60 minutes with little walking and minimal elevation gain. If you time it right you and your friends can get the whole tour to yourselves.
The backstory the tour guide gives you, is interesting and the views of the cave are amazing.
Be sure to bring a light jacket and shoes that will not slip on the sometimes wet floor.
If you are a AAA member you can get a discount on admission.