Those could be some old WPA projects. Highland and West Park are the two oldest parks in Joliet, and Highland had just worn down over the years. Erosion has really taken a bite out of the property. There is that ball field right there by holes #3/#4, when you walk by there you can see where they blocked off a road up there. It's the same road you come across later. It just washed out from erosion and was closed. Anything that was over on that side of the park became somewhat inaccessible once the road was closed and fell into disrepair. Now the neglected remains give it this cool/weird vibe, especially in the #12/#13 area.
