That sounds like the neigbourhood I grew up in. There was a huge park behind my house that was kept a wilderness and we would be in it for hours on end. We would also build forts into the hillside.
We had a small grove of pine trees and a apple tree (and this was a fairly average sized city lot) in which we used to build forts and teepees and tree houses in the apple tree. Indians lived in the “forest” and we would hunt them, or sometimes we WERE the Indians and we’d set up Indian camps. But the best part was, all that packed-down dirt under the apple tree where no grass would grow was great for playing marbles. Fun stuff! Your childhood sounds like mine.