Best Left Forgotten (To the Nucleus)

Pine Crest Cavern: Head west and slightly north from Old Pond House to find the cavern entrance. Clear out Trappers and Turrets. Search the houses for locked Chem and Explosives Boxes, and Ammo Boxes. Descend to the ravine, proceed north, and enter the cavern. Clear the Trapper camp inside, loot the Steamer Trunk. Continue east through the structure to a tunnel, dismantle a Turret, loot Ammo Boxes, and head west to Kitteredge Pass.

Kitteredge Pass: Proceed north through the tunnel to a pit. Drop down (consider using explosives first) to face Ghouls. Venture north to a fork, then west to another fork. Going west leads to an exit, but without a map marker. Going north leads to a dead-end with a Trapper and Ghouls; kill them and loot the Trapper and nearby boxes. Return to the first fork, head north to a chamber with Ghouls playing possum; use VATS to find and kill them. Loot the area, especially the Steamer Trunk. Head east through a tunnel to exit and gain the Kitteredge Pass map marker.

Horizon Flight 1207: Head north-west from Kitteredge Pass to find the crash site and Erickson, a Super Mutant who sells guard dogs for settlements (250 Caps each), ammo, aid, and the legendary Meat Hook "Butcher's Hook". Hack the Terminal (Advanced) inside the plane to access the cabin. Loot the Industrial Trunk, but be aware that stealing will likely turn Erickson and his dogs hostile.

Initiation: Fast-travel to Pine Crest Cavern or head west from Old Pond House. Cross the water using a land-bridge or by swimming. If using the land-bridge, head south along the shore from the western end, looking for Children of Atom flags to the west. Head north-west, then west to reach The Nucleus. After witnessing a loyalty test, approach Grand Zealot Richter to be interrogated. Express interest in joining the Children of Atom. Richter will direct you to drink from a holy spring, initiating the quest "Visions in the Fog".