12 circuit fuse box $50, Wiring loom $50, 18 pin firewall connector $80, 14 & 10 guage wire, 8 colours 50ft lengths $200 to $400, heat shrink, misc pigtails connectors etc! $50. Labour 12 to 20 hours to peg-board and mfg a harness from scratch, since I charge out my labour at work at $95 I'm lucky I not charging myself for this job!
But you get the idea why a painless kit is so much more attractive than repairing what's there, or replacing with OEM. And I do this type of thing for a living, just on much larger and sometimes simpler equipment, and have rebuilt a half dozen classics before, but this is my first Mopar and first major electrical issue, I figured after repairing the electrics on a 46' Ford, 72' MG, 58' & 77' Triumph and a 66' Jag, the last four all British, all with a nasty reputation for electrical faults, that a 60's Plymouth would not be that hard. But I guess the myth about the British wiring, is just that, a 'myth'
Thanks for the input Guys, I would like to do it the ways you have suggested, and I do see the merit in them, but deadlines and money dictate a different route!