Robert - if you don't have a background or experience in wiring you will have a learning curve. You are going to need some tools and have to develop an understanding of how all this works. It is definitely doable, but takes a methodical approach and an understanding of basic electrical principles; in other words it is not something you are just going to stab in there and everything is going to work especially if you want to use the factory switches, gauges, steering column, wiper motor, etc. All of these things will require you to understand how they were designed to work and then adapt the harness to them. Again, totally possible but just not super easy. Harnesses like the Kwik, Painless, etc. are designed for hotrods primarily and while they give you all the circuits you will need, it is up to you to figure out how to make them work.
When I built my Cuda I used a Kwik 14 circuit harness, but I basically tore it apart and rebuilt it to match my car. I had the dash out on a stand and installed the fuse box into the glove box area and then ran all of the wires as I needed them. I ran a lot of relays for certain things such as my push button start. I have a 2" 3 ring binder full of wiring diagrams, some provided, many of my own design.
Mopars (as well as the other brands of the era) used a connector called a "Packard 56" or just Packard. They are available currently in a variety of configurations (1, 2, 3, 4, wire). They are comprised of a male and female connector (generally need to be purchased individually, 4 parts; the 2 housings and the 2 connectors). They require a special crimper to assemble which is stupid expensive, however there are work arounds with less expensive tools. I also use Weatherpack and Metripack connectors in certain places like under the hood or anywhere exposed to moisture. The Packard connectors were good for their day and they can take more amps than the others, but they are not sealed so they are susceptible to corrosion. These other connectors have their own nuances for assembly which you will have to learn. I solder every connector I make, some will argue that the car manufactures don't and therefore the hobbyist doesn't have to, however I would argue that the manufactures not only have better equipment but they have better assembly techniques and there are few things that will piss you off more than electrical issues, specifically a non contacting terminal (which cannot be seen).
All this said, it is certainly possible to use the Kwik system or another one like it, however it comes at a cost. If electrical work is of interest to you or you have a background in it then go for it. If you have never done any electrical work and have little or no interest in it, I would strongly recommend against it.
Do you have the original harness? One option is to remove the original and remove the wrap that is usually on it zip tying the harness as you remove the wrap so you keep all the wires together as they were originally. Then take one set at a time and trace every wire repairing or replacing as needed. You could conceivably rebuild an entire harness this way, but it will be tedious but far cheaper than buying a new one. You can reuse most of your original connectors and get some Packard male/female terminals to replace worn out or damaged originals. You will still need some tools but you have a road map to where you are going. Granted the original harness/electrical system was not the best, specifically the aspect of how Mopar ran the alternator wires, but you can address this when you do the harness by upgrading the wires with heavier wires and re configuring the harness based on the many guides online (here included) to basically bypass the amp meter.
There are some Mopar specific after market harnesses out there, but from what I am seeing they cost as much as the originals; sure they are probably better in terms of routing and quality of wire, but they still are going to require an understanding of how it all works and the tools to install it. I've been doing Mopar electrical systems since the 70's and I can say with authority that there is no easy way to do this other than getting a repo plug and play harness and even then there are challenges.
Whatever way you decide, we are here to help
