Harness???

I'm going to replace the harness's in my 68 Dart. I'm not an expert with electrical so I need recommendations on easiest install of new wiring harnesses. Thanks in advance.
Details..
1968 Dart 500ci stroker, MSD 6AL, MSD Billet Distributor, Electric cooling fans, Trunk mounted battery.

It is all custom so an appropriate harness(s) will need to made and fabbed. I would recommend going to an electitrcal shop to have it built if you have limited experience. There is no plug and play option for you so to say. Aftermarket is the only way is only way to go and the factory service docs will only provide limited direction. You can buy some books and reference the factory docs but if you are not very comfy about it, leave it the experts.