You can see my photos of the nurses quarters in a previous post which is on the mainland. If you walk down the main entrance road you will come to a tunnel to your right which takes you directly to them. If you walk further there is a guards house at the top of the hill. Which over looks the bridge to the island. If you have a kayak you can park at the carpark at Mooney northbound and paddle around to the back of the island.
Please don't ask where this is or how to get in, its called urban exploration. if you are told the location and how to get in, its tourism not exploration"