Ever thought about the wiring in a camper van? We have. This is the looms going into our first camper. Note that we use harnessflex throughout and don't just pass exposed wires through the bodywork. It takes longer and costs more, but electrical faults in campers are a nightmare to repair so we think it's worth doing it right first time!
Once it's all in there's quite a few connections to be made - it looks untidy - but it will all be hidden away when complete.