Does anyone know if there's a day trip by bus guided tour from Northern Virginia or Washington DC to Luray Caverns.
Google shows me there are a few tours to Luray Caverns from Washington, DC that run about $60. However, if you have access to a car, or can even rent one for the day, I feel like that's a much better way to go. Your $26 entry fee to the caverns already includes a guided tour and having a car frees you up to do other things in the area.
For example, you can pair the caverns with a visit to Shenandoah National Park - take Rt 66 to Front Royal (canoe capital of Virginia), and head down to Luray on Skyline Drive. Stop for lunch in adorable Sperryville - I'd recommend the Thornton River Grille - or drop by one of the many wineries in the area on your way back to DC.
Mentioned in this answer: