It is at the 2,500 feet above sea level contour.

I found the maps, but I have yet to find the room descriptions. I added new room descriptions.

After clearing the dirt for 20 game minutes a stone plug will be found in the center of the stone ring. Attached to it is a rusty iron ring.

Pulling up on the ring with a combined strength of 25, will raise the stone plug. Up to three characters can get a grip on the ring. Removing it reveals a stone tunnel going downwards, which is 5’ wide at the top and 10’ wide at the bottom. The wooden ladder is long gone. The drop is 15 feet.