I have rewired my truck one wire at a time. Very easy to do as long as you have good wire, connectors and a crimping tool.
There is a schematic in the back of the shop manual which also specifies wire gauge. If you are going to 12v you can use a smaller gauge wire.
The only difficult part I had was accessing the instrument panel because of the tight working area. However that same problem exists even if you are using a new wiring harness.
If you need more either Email or send me a PM.
Bill
