When you enter, you will make a left turn and enter a circular room with a pillar in the middle. On the other side of the room is a slope that leads into yet another circular room. This room contains two campfires, four beds, six sacks containing minor loot (taking from these sacks will not lower Karma), a bunch of fruits and meats scattered about the room, three logs to sit on, and some Sorrow tribesmen walking about. If you turn left and continue walking toward the second camp fire you will see a door that leads to a higher part of The Narrows.
Just before the lower entrance to the cave there is a cowboy hat, a metal pan, and a set of arms and legs centered around a large rock. By Clark's terminal entry found in the cave, it is likely these are the remains of the pointman who was crushed by the deadfall.