Yao Guai Tunnels

The Yao Guai Tunnels are located due west of the Charnel House, and northwest of Smith Casey's Garage. The entrance is a chain-link fence door in a rocky outcrop. As expected, the caves are inhabited by a number of Yao Guai. There is also a bottle of Nuka-Cola Quantum here.

Since all of the enemies here are animals, the "Animal Friend" perk will cause them to ignore you.

Bobblehead Location
To find the Sneak bobblehead, turn north at the first major intersection and follow the tunnels to the door to the Yao Guai Den. Once inside the Den, walk straight ahead to the central pillar, and then bear left. Immediately look for the natural stone ramp that leads along the eastern edge of the cavern, overlooking a crescent-shaped pool of water. At the base of the ramp is a Metal Box with the bobblehead standing on top of it.