Chamber B is south of Chamber A. Chamber C is west of Chamber B and southwest of Chamber A.
and then make clear in the description text that both doors lead out along the same wall. If you’re standing in the middle of Chamber C, one of the rooms is going to be more northeasterly than the other- both doors to the rooms can’t be in the exact same cardinal direction relative to an onlooker. To have Chamber C be west of Chamber A, you can say something like:
Before going west when the player is in Chamber A, try going southwest instead.
If you really wanted to you could have some sort of disambiguation (“Did you mean going east to Chamber A, or east to Chamber B?”) when the player tries going east from the Chamber C, but that’d be really annoying.
Your house is a fun thing to model when you’re learning Inform but often makes for a terrible game; so unless you end up with solid gold on your hands, resist the urge to publish.
The Pub, the Gents' and the Ladies' are rooms.
The Gents' is southeast of the Pub.
The Ladies' is northeast of the Pub.
The Pub is west of Gents' and west of Ladies'.
Understand "east" or "e" as a mistake ( "You can go northeast to the Ladies['] room or southeast to the Gents['].") when the location is the Pub.
When modelling real houses and trying to have inform rooms match real rooms, it soon becomes obvious that real-life architects rarely have the consideration to lay out houses in square grids aligned neatly to the north-south line. One thing you could play around with if you wanted to be more faithful to a complex layout is eschew cardinal directions entirely, and have the game behave like the following (although, hopefully better written):
I don’t know how much success games have had using this sort of thing. It would seem more intuitive given that people (other than aborigines) tend to navigate using relative rather than absolute directions. We say, “turn left, left again, then right”, rather than, “when heading north, turn west, south, then west again”.
Alternately for rooms like hallways, you can just break it into two rooms and have Room A west of Hallway North and Room B west of Hallway South. This increases your travel time and can seem odd when you can’t see an object at the other end off the hallway, though.