There, a strange gap in the wall or the foliage—where does it go?

There is a secret tunnel in this area. Roll 3 dice to find where it ends:
6: Any zone.
4-5: Either the General Store, the Shopping Street, WcDonald's, or the Swamp.
2-3: Either the Clinic, the School, the Forest's Edge, or the Water Park.
0-1: Either the Junkyard, the Mountain's Edge, the Construction Site, or the Abandoned Mines.
You can then use the secret passage at any time, from either end.