I know a few locations, in NewHaven the is the Lumber Union in the building infront of ur spawn, the Mechanic Union is in Bartonville, Mining Union in Orrsville, the Buyer on the barge in the ocean, the Hunting Union in a building near Charleston, the Pilot Union is in a building near the garage place a bit away from Wellston, the main police Union as at the Keycard locked door base thing near Bristol, and the Keycard person is under kensington hights. the Supplier is in a discuised bunker thing out in the wilderness, Catherby Resort has the Fishing Union, the Farming Union is in Chesterbrook, Portland has the EMS but its quite glitchy. i think thats all, hope this helps. (BTW the NPCs are on ChefCounty)

There is a second supplier southeast of bristol in a tent, kinda hard to find but its worth it :P

Where, EXACTLY is the bartonvillie NPC?

on chef

yes. Like as in the one that sell cheap roadsters.

https://gyazo.com/d8d341ab57e7b8a07851ef56dfcbb22c

where is berry dealer?

Cheaters