Children play a game outside on the grounds of Copper Cannon Camp in Bethlehem. (Photo by Maya Mitchell/New Hampshire Bulletin)A mile-long dirt road, nestled in the woods on the outskirts of Franconia Notch State Park, separates Gale River Cooperative Preschool from its neighbors. The school is hidden, not just because of the deep woods surrounding it but because it’s located on the grounds of a sleepaway camp. For 10 months out of the year, Co…