Unless something has changed recently, it closes when the park does. It's really stupid, you would think they would want to stay open and get the rush of people after the park closes. There were a few times that I left at midnight only to find the place closed.
"You can cut me off from the civilized world. You can incarcerate me with two moronic cellmates. You can torture me with your thrice daily swill, but you cannot break the spirit of a Winchester. My voice shall be heard from this wilderness and I shall be delivered from this fetid and festering sewer."