Yeh i see what looks to be 5 sets of wire installs? If that was me, I would start by buying a bunch of different color wires, wire loom plastic and some better than radio shack quality connectors, and just build the wire harness one wire at a time from scratch.
Anyway I would try and route it like this one main harness with a few legs comming off the main one:
If you build it from scratch yourself you can make the wires all length to fit, wrap everything in black plastic wire loom and it would look like a proffessional install. Again the mods themselfs are cool, just the insides need some staightening.