In Fable 3 for the Xbox 360, there are four gold key doors scattered around Albion that you’ll need a gold key to open. You can use any gold key to open any of the gold key doors.
Bowerstone Catacombs Gold Key Door
This gold key door is on the path in the catacombs beneath Bowerstone Castle. Easily accessible once you have access to the castle. There are 30 guild seals located inside.
Brightwall Village Gold Key Door
You must first complete the Special Delivery quest in the Dwellers camp. Next, start The Ancient Key quest in the academy. During The Ancient Key quest, you’ll gain access to the Reliquary, which is where the gold key door is located. There is a secret library inside of the Reliquary. Inside of the secret library, you’ll see a flit switch. Hit it four times with a firearm to activate it. Go upstairs and through a door on the left to find a melee flit switch. Once you hit it, it will float down to a lower section. Go down and hit it again, and some waves of Hollow Men will come. Once they are defeated, stairs will open up leading to a platform to open the gold key door.
Mourningwood Gold Key Door
First, you need to complete the Bored to Death and Gone But Not Forgotten side quests in Mourningwood. Once these are completed, you’ll gain access to the Ossuary. Once inside the Ossuary, go left right after you enter and you’ll see the gold key door. Inside you’ll find a legendary weapon.
Sunset House Gold Key Door
Inside the main gate to Sunset House, go right once you’re on the lawn. You’ll find a winding path that leads to the gold key door. Inside you’ll find a legendary weapon.