There are a variety of different ways to wire a dollhouse depending on the complexity of the lighting system and what you want to spend. The most common lighting system for dollhouses is tape wire which is fairly easy to install but it does have its disadvantages. Tape wire is usually double or plastic coated copper tape. Using a tape wire the electricity is all on one circuit so if one light goes out they all go out. There also can be problems where the tape joins. This type of wiring usually runs on the walls.Another type of dollhouse wiring is the round wire system. This type of system is more
sophisticated than the simple tape wire. In a round wire system the all of the wires go to a wiring board which is usually located on the bottom or back of the dollhouse. The wiring is direct so that each light fixture is independently wired to the controller. You can use plug in lights with this type of system and if you want to get fancy you can add dimmers or a remote control system. The wiring will need to run on the flooring or under molding.There are also combination wiring systems that are hybrid in nature using both tape wire circuits and round wires which run to a power supply. If you decide to install the lighting system yourself there are several good books on the subject including the Dollhouse Tape Wire Instruction Book, How to Light a Dollhouse by Jean Dickey and Miniature Wiring for Dollhouses and Miniature Rooms by Ed Leonard.