Don't get so hung up on the 12-volt conversion as most all wire connections are the same. The coil you have covered since it is internal. Lights are the same since you just change bulbs. On the fuel tank power you have to put a resistor between the gauge and the tank or it will fry it but that is the major piece. I put a runtz type resistor off the back of may gauge for the fuel tank that is just one wire. On these old trucks most of the grounding is to the frame so you are only running single wires. I have some good diagrams that came with my harness I will scan and mail them to you it may help. I will get them to you as soon as I can find them.
