[Splat]

In case you don't want to relinquish the challenge and use a walkthrough, here's my advice.

Often (but not always) in the first passage of Rupture Farms, both when you leave and return, you can hear a slig walking or snoring when there isn't one in the screen or any neighboring screens; this usually means there's a secret passage in the screen. Try hoisitng behind things or dropping down trapdoors. Also, when you return to Rupture Farms all the secret passages you cleared out when you left will have been repopulated.

Spoilers:
(Don't know how to do spoiler tags so I'm just sticking it in tiny writing)
There are three secret passages in Scrabania, one in Paramonia and none after your first ballcar ride. Everyone else is in the first tunnel of Rupture Farms or the Stockyards.