It appears you have some mechanical ability. Probably enough that you can repair what's there. I suggest getting lots of shrink sleeve and a decent heat gun. They're cheap. You can get a wire gauge and measure the gauges of the wire and get the correct colors and gauges from most any parts store. Looks like you've already made a few repairs already. I would take a deep breath, follow your wiring harness and fix it one wire at the time. It's time consuming, but you can rebuild that harness one repair at the time. The only thing that might hinder you is if the insulation elsewhere is dried to the point it's cracking. If that's the case, then another harness might be best. Speedway Motors always has good prices on harnesses. Now, they are all GM color coded, but big whoop, they are all marked on the wire what they're for and where they go. No firewall connector. That's a big point of contention on a Mopar. They always give trouble over time. Here's a 22 circuit complete harness from Speedway and it's on sale.
22-Circuit Universal Automotive Aftermarket Wiring Harness Kit
Now, I'm not suggesting you jump right on that, because it looks like you're gettin it done. There's a lot of reward in making something good out of something bad. I love doing it. Sometimes though, it's best to start clean. Without being there and seeing all the rest, that's a decision you're going to have to make.
