Embark on an island trekking adventure on the third day. Choose one of the larger islands, such as Governor Island or Children's Island, and hike through their lush forests. Enjoy the scenic views and spot various flora and fauna along the way. After the trek, head to the zipline area and experience an adrenaline rush as you zip across the islands, taking in breathtaking views of the park from above. In the afternoon, relax on one of the quieter islands, have a picnic, and enjoy the tranquility of nature.