GM: "OK, you're on your way to the Forbidden Mines. You pass through a lightly-wooded area that shows signs of previous civilization: the odd ruined wall or ancient, crumbling tower..."This is one of the reasons I did the Chamber Generator. Zak S. suggested a way to deal with it: let the players investigate the tower, but generate enough details about the purpose and background of every door to enable you to improvise what's behind it, enough to satisfy everyone. That's what inspired me to talk about my own solution to doors: the initial d12 table, the follow-up on the purpose and background of random doors, and some example doors. But now I want to walk through an example of how to use this in play, in a situation like the one above.
Player: "Wait! Crumbling tower? Let's go check one out!"
First: Think about what you can assume as the basics. In the tower example, there's a couple of obvious basic front doors, plus we can assume the front door leads to an entry alcove that can double as a guard station, with another door leading to the main hall. Somewhere in the tower will be stairs of some kind.
Let's go with a portcullis as the outer door, with a winch mechanism in the alcove, and thick double doors from the alcove to the main hall. We don't need the purpose of these doors, because they're pretty obviously defensive... although we *could* roll for a different purpose. We'll enter from the North side of the tower.
Second: Elaborate existing elements. To begin with, we might want more detail for the tower itself. A simple reaction roll to determine the mood or tone, rolled on the dice map, will do the job. We'll treat all "door" results for this roll as "Feature" results, because we don't need more exterior doors.
Reaction Roll: 6; Spatial Orientation: (H2) MH4.
An Average result for reaction, so it's just a very weathered-looking tower, no hint of danger, malice, or for that matter reward. There's a container beginning with "H/Ei/K" and some kind of "furnishing" beginning with "M/Oi/P" and "H/Ei/K" outside... a small keg and marble hitching posts would do the trick. What's in the keg? Pick something at random, or roll.
Each fact suggests interpretations, which will help flesh out the next random detail. A hitching post? Sounds like visitors on horseback came here frequently. But marble is kind of fancy, so maybe this tower served some kind of public, official capacity. One of a series of way stations and signal towers? We've already said it's ruined, but if that keg is in good condition, someone's been here recently. This tower has become someone's lair.
We also need the status of the portcullis, and could also do with a descriptive adjective, so roll 1d6 on the map.
Door Status: D1.
The portcullis is half-raised and made of thick logs bleached white with age. The party will have to crawl under one by one, perhaps risking the portcullis crashing down.
We'll go easy on the party and not put a monster on guard, but we do need a status for the double doors, and maybe another descriptor, so roll the d6 again.
Door Status: J6.
The doors are locked and have ivory handles.
Again, the details add to our impression of the tower. Fancy ivory handles confirm that the tower was once an official outpost, not a secret hideout. The locked door and poor state of the portcullis suggests this door may not be the current main entrance; there may be a hidden access somewhere.
Third: We know basically what's behind the double doors -- the main hall -- but don't know what's in the room or what exits might be there. For this, we use the 3d6 roll, with one die a different color than the others. This lets us make three simultaneous rolls: a 3d6 dice map roll, a 2d6 reaction roll (for the tone of the room,) and a 1d6 stocking roll (to tell us if there are monsters or treasure in the room.)
Reaction Roll: 7; Stocking Roll: 3; Spatial Orientation: D1 H6 ssw3.
Again, an Average result for reaction, and the room has no monster, trap, or treasure. The floor is covered with dirt, the ceiling has a hole in it (we could have made the ceiling "high", or covered with "knotted" ropes.) There's one door almost directly opposite the entryway; the door's status may be "jammed", but we won't be certain until after the d12 roll.
Door Roll: G8
It's a hidden door, so we use the "G/Ou/N" to describe what it's hidden by/behind and make a reaction roll for the tone of what's behind the door. A door hidden by "gold" wouldn't be hidden long, and "guts" doesn't fit the tone of the main hall itself, so we'll say it's hidden in a "Niche" behind a "goat-hide".
Reaction Roll: 11; Spatial Orientation: DJ5 G6
The people who hid the door really like what they are trying to hide. We could use the letters indicated by where the dice land for suggestions. A djinn lamp and a golden staircase? We could drop clues to the lamp later, but there'd be no obvious signs here in the tower. It may turn out that "djinn lamp" doesn't mean a lamp that grants wishes, but might have something to do with signaling over long distances. Perhaps these towers had magic lanterns, made by a bound djinn, able to bear messages over long distances.
Fourth: What kind of area is immediately behind the hidden door? We use the simple 1d6 roll to determine that: we get a 4, which indicates a squarish room, as would a 5. A 6 would have been a rectangle, a 2 or 3 would have been a corridor, a 1 would be a dead end. Since this is a tower, our mapping space is constrained, so we will want to shorten some corridors, shrink some rooms, or flat out ignore further mapping rolls.
Fifth: If this is new area is a room, we follow up with the same kind of 3d6 roll we used to describe the main hall in Step Three. For a "5" result, though, we would roll 4d6 instead of 3d6; similarly, we roll 1d6 on the dice map for the contents of a dead end, and 2d6 for the "end" of a 60-foot section of a type "3" corridor; type 2 corridors get no such roll on the dice map, but instead repeat Step Four. Again, for a constrained space like a tower, some door results will lead back outside, or can be transformed into (obvious) trap doors in the floor or ceiling to lead into a new area.