Gilbert Lake State Park was one of my favorite attractions when I lived in the area. Minutes from Interstate 88 near Oneonta, it is chock full of hiking trails, several ponds and lakes, and places to bike. During the summer, there is a beach open for swimming, and there are campsites you can bring your RV to as well as cabins to rent for a small fee. There is a fee to enter the park with a vehicle during the summer, but before Memorial Day, parking is free and after Labor Day it is as well, except on weekends before Columbus Day. Beautiful place, and highly recommend it.