After your brief reunion with extended family members in Strigastadt, you are handed a parcel they hope will serve you well in your planned scavenging forays. The handful of objects belonged to your cousin before her untimely passing. A member of the Sewer-Militia, she had carried this map with her on her last detail, and it bears the grime of repeated use. It appears to be some sort of schoolchild's exercise - a map of Strigastadt's boroughs all unlabeled. In tiny script, your home borough of Krüger has been labeled in an abortive enterprise to fill the blanks. Perhaps you can finish the job.
My intention is for the party to explore the devastated Grey District from the start of the campaign, and move to city-crawl like adventures in the East End after they've gotten a handle on the place. I've divided the city into boroughs which are composed of a double fistful of neighborhoods each, allowing several levels of abstraction as needed. Each is as-yet unnamed - I will generate them as the PCs travel, allowing us all to explore the city together.
Some notes on the setting - the Grey District has lain mostly deserted for the last hundred years since it was devastated in a great war, primarily by the use of chemical weapons (such as Black Smoke). Terrible monstrosities rose from the ruins, and plentiful undead roamed free. The weakened city heads cut their losses, demolishing the bridges to quarantine the worst of the damage. Since then the worst of the chemicals have stabilized and while things are still terribly dangerous, hardy and desperate souls have begun to scavenge in the ruins, picking over the abandoned dwellings of a century ago.
For Strigastadt I have been primarily drawing from Wermspittle (obviously), Cörpathium, Vornheim, and of course, Gormenghast. Wermspittle for the wonderful mashup of elements from the last couple centuries with fantasy, Cörpathium for its beautifully mad creativity (especially their Maleficar!), and Vornheim for the simultaneously useful and inspiring random tables. I'll mention elements I'm using from time to time when they are germane to whatever tidbit I'm posting, but know that I am gleefully lifting sections wholesale - like ransacking a liquor store and greedily guzzling the finest spirits.