Sometimes I will just shut off all but one circuit and do a walkthrough of the house with a receptacle tester and a notepad making notations as to what lights and receptacles are on that circuit. This is pretty time consuming for one person though, especially with a building like in the OP’s case. That’s one reason I would like to try out one of those circuit mappers next time this type of situation comes up.
I have one of those TestUm Lanscaper network cable mappers with 8-remotes and a bunch of different adapter cords, but I never actually thought about trying it on deenergized line voltage circuits before.
I know if I unplug lamps and small appliances from the receptacles and turn off all the wall switches for ceiling lights, I can use a toner/probe to trace a deenergized circuit through the building this way, so maybe I’ll try the network mapper around my house and see how it works out.
