I live about 20 minutes from Cave in Rock Park. very beautiful park . there is so much ground to be covered and some places are quite rugged. i'm not sure about what is off limits there though. i havn't got a permit to detect there though.
Searched the cave and area 32 years ago and I did not find any thing; old party site and dug like 100 pull tabs and bottle caps.
The rugged river front area would take time to search out lying areas.