This isn't so much a maze as a slum packed in as much as I could. I could have used just nw alley's but it's part of a module I'm working on with ships [carrack's etc] so it uses silver cloud's sc_bb_ultilmate.hak.
first I made the city gate [for connecting to that module I mentioned. Then the rest I filled with buildings. After that I put alleys in lanes both n-s and e-w. I adjusted alleys so every building group had at least one door. there are a LOT of doors. I counted 142 not counting that gate door.
There are no interiors! There are no npcs. I leave that to others.
Ideas:
You could creat keys for every door and lock them and sell the keys as real estate ploy. In richer area charge more. In these slums, let the players have their pick but put a bunch or others houses with nasty bandits hiding out. hehehe. And put some plot and sub plot items some where in the various houses. hehehe. lock all the doors, and all the doors without keys [for real estate uses] load with pickable locks and traps, and nasties in every one of them to kill off before finding if that particular house has anything of value to you. hehehe.