Start with a blank sheet of paper and build a wiring plan. The Trillium
wiring diagram in the document center is a good place to start. Exterior marker lights and tail lights
are powered by the tow vehicle.
Key decisions include where you are going to install a power control center, how you are going to attach to 120V AC power, how many 120V AC and how many 12V DC circuits you want, how many amps will you need for both types. Separate circuits allow you to isolate problems. For example, my 1977 Trillium
came with ONE 120V AC circuit and ONE 12V DC circuit. It now has several of each, bigger converter, etc.