With the right wiring (like the harnesses from M&H Electrical http://wiringharness.com ) you do not need ANY prior experience to rewire the entire car. You can also buy only the harness segments you need (forward lamp harness, engine harness, dash harness, tail lamp harness, and each of the accessory harnesses).

You do need a camera to document the routing, and masking tape to mark where the old connectors attach. I use paper tags with strings on the new harness and mark them the same as the old, as they remove easily with no residue.

With care and patience you can undo the sins of previous owners and repair your existing harness. Be sure to do it properly, and insulate and tie down the wires well. If the fuse block fuseholders are brittle or badly corroded, or if the wiring is stiff and the insulation brittle, replace it all.