On the northern coast of California, just minutes away from the Redwoods, the glow of the Battery Point Light spills out across the water each night, warning passing ships of the rugged coastline. One of the oldest operating lighthouses in the state, the museum-in-a-lighthouse has been active since 1856. The lighthouse has been automated for decades, but resident caretakers continue to inhabit the building, tending to the tower, operating the museum, and offering tours of the premises. Over the centuries, the tiny island on which Battery Point Light is perched…