The upper-most level is a cave system of interconnected tunnels and a large central cave, currently occupied by bandits raiding the countryside. Perhaps there are hints in the central cave that something more lies beneath, but the brigands have ignored them. Perhaps they’ve heard the sounds of a large animal in the caves below and, unable to find it or unwilling to encounter it, they avoid going deeper.
In any event, the people hiding in these caves have been here long enough to construct several crude structures and cultivate a simple mushroom farm at the rear.
“It’s clear the brigands living here never bothered to climb this ledge, but simply threw their garbage up here to rot. Carved into the stone are images of bears and men hunting elk together and indecipherable runes.”