I 'repurpose' any Dvergr outpost I can find and 'liberate'....terrain wall off the ends of the small valleys nearby and 'purify' the land with workbenches!

I've got a NPC free zone right now where 3 small valleys converge...it's become my Mistland farm for Mushy's...sure I can hear the Gjalls nearby....been okay so far, once I walled off the valleys.

Keep yer crops out of LineOfSight, with walls, etc....I've got both, fenced in with stake walls and some open patches on the ground.