While TftL mainly takes place on the Mälar islands, there are more references to the mainland in "Things From the Flood", like the Krafta HQ, the radio telescopes, the tower apartment blocks, and so on. The Greater Stockholm neighborhoods of Hässelby, Järfälla, Vällingby, etc, are just across the water from the islands, and only accessible by boat. The only land connection are the bridges to Lovön in the southeast, and then by road to Stockholm.
Is there interest in expanding the geographical setting, if only to add the locations in Simon's art? While Kids might not be allowed to go there by themselves, they might have family there, or run away. If - as I've suggested - an TftF expansion allows for characters aged up to 18, they would probably want to go to the mainland and downtown Stockholm. An expansion would at least need to address the locations in the illustrations.
So, what would you like to see? For those of you who don't own the book, the relevant art starts about halfway down this page.