I used to work for US Air, on airplanes. We had to run miles of wiring to all of the airplane instruments and other components.
This wiring is mainly just input to output, in to out, over and over. I made a couple of switch boxes to jump back and forth between clean and distortion tones.
I just sad down and wrote it all out on paper, then through trail and error kept messing with it until I got everything sounding the best that I could do.