The Catacombs Golden DoorEdit
This Golden Door can be accessed through the Catacombs beyond the Hero of Bowerstone's tomb. The hero's first encounter with this door is during the exodus from Bowerstone Castle during the first part of the game but is unable to be accessed until the hero collects a Golden Key which can be found later in the game. After opening this door, follow the path downwards and you'll run into a random party of monsters. Take the path to the left and go up a rock spire. At the top of the spire is a chest with 40 guild seals inside.
Sunset House Golden DoorEdit
This Golden Door is located in the woods to the right of the Sunset House as you pass through boundary fences. You do not need to complete the Sunset House sidequest to gain access. A chest with a random Legendary Weapon is found beyond the golden door.
Reliquary Golden DoorEdit
A third golden door exists in the Reliquary of Brightwall Academy where several quests occur. Close to the locked Silver Door (requires a key from Saul's quests) is a Flit Switch which leads to several more Flit Switches, ending in the central atrium.
Activating the final flit switch will cause a platform to appear. To begin your descent, simply step on the glowing arrow on the platform. This will summon a new platform with its own glowing arrow, which will summon yet another platform. Continue stepping on the arrows (while fighting off occasional Hollow Men attacks) until the staircase reaches all the way down to a Golden Door.
Inside, you will find a Cullis Gate to The Prism. You must then travel through a series of different Cullis Gates that lead to chests guarded by Hollow Men. The most efficient way to use the Cullis Gates is to always use the one on the left. Looting all of the chests earns you the entire Men's and Women's Highwayman Suit, which costs about 20,000 gold each in a clothing shop.
There have been reports of a bug when going down the raised platforms. If you stop halfway down, walk out of the area and come back later, you can't continue down the stairs, as if there were an invisible wall. It is not currently known whether this can be rectified.
The Ossuary Golden DoorEdit
This door is in the Ossuary dungeon area. This area is unlocked during Gone But Not Forgotten, which is unlocked by doing Bored to Death in Mourningwood . Upon entering the area you will have to ascend a flight of stairs and run along the top to reach the other side of a chasm. Halfway across this balcony area, you'll clearly see the door on your left. The inside is filled with coffins; go up the stairs and there is a sarcophagus containing a random rare legendary weapon, the cream of the crop available from the "Good" alignment selection pool. (Exceptions to the elite "Good" alignment weapon pool are sometimes chaotically observed, and, if veraciously reported, of completely unknown meaning.)