Skyline Wilderness Park is adjacent to Napa State Hospital and Syar's mining pit for coarse aggraget used for concrete mixes. You can get close enough to the ledge to see the giant pit and likely toxic water pit.The park contains many trains and you can see the remains of some mining operations (likely for mercury) complete with pick axe marks. There is also an old home carved into the side of the trail with what appears to be a concrete table and hearth. Elsewhere you can find abandoned buildings, piles of old, very rusted cans from decades ago, and another hearth carved out of the side of the hill next to the Syar pit.