If you turn right coming out of Pepperpot cave and follow the path you’ll come upon this fence. Hop over, and climb the hill. You’ll find a large building, and around the side is this key.
From the lake, take the path up the hill that leads to The Hole and Pepperpot Cave. You’ll soon be able to venture off the path to the right and find this key perched here.
Across the main path from the area where you found the second key, you’ll be able to traverse the terrain and see a key in the pond. It is just below the telescope statue.
(Reaver’s Manor) When you accept the “Reaver’s Unmentionables” quest, you’ll eventually wind up in this secret bedroom. The key is behind the bed.
(Pepperpot Caves) Swim across the pond in this cave to reach a silver key.
(Dankwater Cavern) You’ll need to have “beaten” the game before you can access the “Hobnobbing with Hobbes” quest which unlocks the Dankwater Caverns. Beat the quest and return to the area after a bit to have full access. Near the hobbe camp, enter the water and hug the rocks to the right as you swim. This path will take you to some land. Walk up the shore a bit and find this key.
(Dankwater Cavern) As you continue through the cavern, you see this narrow path leading up and to the right. Hobbe’s will probably flood down this path at you. Go up here to nab the silver key.
Mistpeak Valley (6 Silver Keys, 1 Gold Key)
Behind a stack of logs near the entrance point to the Merc Camp.
Coming from the Monorail Station, turn left and follow the path up the hill to find this key.
(Chillbreath Caverns) You need to enter the caverns from the area accessible by crossing the small bridge overlooking the Mistpeak Valley Demon Door. Once inside, follow the path a ways to find this key. It’s right near the missing child.
(The Hole) Behind this rack of barrels, near the technician’s gate.
(The Hole) Open the technician’s gate and follow the path all the way to where you see this key on some rocks overlooking the arena.
(The Hole) You’ll have to enter The Hole from Millfields to find this key on the monorail platform.
At this signpost on the path to Brightwall Village, hang a left. You’re going the right way if you pass a treasure chest on your right. Your goal is to pass through the Chillbreath Caverns. The caverns can be confusing, but if you make it a point to keep moving uphill you’ll eventually reach the exit leading out to this golden key.