I wonder if it wasn't possible to premake NPCs with wandering scripts in the editor, which you can place in GM Mode. Maybe even wandering towards certain objects that you also can place in GM Mode. I am by no means any expert in scripting nor in the scripting parts of the engine. Generally i was said no scripting no patrol in gm mode. But i wonder i something premade in editor could work.
Let's see maybe Larian was listening to community mentioning patrols as a need and will implement it in future anyway.
Anybody here that is more knowledgeable than me. ?
This is only speculating, but you could perhaps to a GEN_PatrolRandom script and make 2-6 items, like a rock, flower, book or what ever and have the NPC patrol between those. Then save those 2-6 items + the NPC to GM mod and put them on a map, using the 2-6 items as placeable path triggers for the NPC.
Maybe.
Upon re-reading; Basically what you said, with an explanation added to it.