I don't have anything too ambitious in mind at the moment. Could you be a bit more specific, as there are tons of paths in Port Telvannis. Your just saying not to edit those in any way? Can do. Aside from 2 objects in Firewatch (neither of which are of any consequence, but I can't figure out how to remove them without needing to redo Firewatch,) I have touched nothing but NPCs.
The woodcutter in Port Telvannis only occupies the middle table. If you head straight out of the Port Telvannis entryway at the port, and stay to the left of the stairs, shop, and mushroom root ramp directly ahead, the path takes you clockwise around that end of the city. The tables (they look more like benches) are on your right, just before/as the path bends to the right and heads across the length of the entire city. You're quite welcome to the other two spots, if you like, and there' nothing too urgent to prevent me from finding another location if you deem it necessary to set up a small market or something, but I don't see that as "likely".
I've got a woodcutter set up in Firewatch as well, near the docks. There's a small wooden "booth" along the stone wall that seperates the dock area from the Castle district, and he's standing along the wall beside it, toward the actual docks. It doesn't sound like there'd be any conflict, but I figured that I'd mention it.
Unfortunately, it may be a while before my current character gets done with current affairs and wanders over to the mainland to check for potential conflicts with your mod. Since I'm holding off on any updates until after the next TR release, it might be easier if I work around your mod, rather than the opposite. By that time, you'll have NPCs in most of the settlements, and I can position any future added woodcutters, or adjust merchants' goods, to fit.