Rocky island is a good launching point out to devil's island. If you can, get site number 1. It's out on a beautiful sandy beach. Site 2 is difficult to access. There's no sandy beach and you need to struggle up a steep hill with your gear. Site 3 is in the grey area in between. There's a decent tail to an overlook on the northwest side of the island. A bench to sit on and a view of devil's island in the distance. But I recommend a trail not on the park map. Take the trail past the ranger station, past the group campsite, through the private property (be a good northlander: be polite, say hi and don't mess with anyone's stuff) and down the sandy beach until you reach a large stump protruding from the beach. The trail is on the left and easy to miss. Brings you to a gorgeous beach you could spend the whole day on.