Luray caverns is a great place to do a little safe and curated spelunking, especially with kids. The place is lit very well, beautiful and safe, and kids are really just amazed by it since it's like nothing they have seen before. There is also an auto and carriage history tour on site and also a place called Toy Junction that I did not make it to but which is apparently a nice collection of model trains. If you are staying nearby camping or hiking, which many people do, you could take them up on one of their multiday tickets and try out the rope course or the hedge maze and see the outside grounds as well. Tickets are $28 for adults and $15 each for children.
Points of interest
Luray Caverns Service Road
Luray Caverns is a great place for kids to get some spectacular sites and a science