New wiring harness worth it?

[muddpile]

I was looking at my old 72 today, getting ready for the teardown, and I noticed that the 30 year old wiring looks pretty bad. It's not bare or cracked that I know of, just looped all over the place, spliced, etc. Since I am doing a frame off anyways (or the better part of one for sure) should I replace the whole setup? My truck is low options and will stay that way. It has power steering, manual brakes, column shifted auto, no air, extra gauges but no tach, and the engine and HEI out of an early 80s suburban. Is it worth it to get a new harness, or should I just try and sort the old one out and tidy it up a bit?

Also, how hard is a new harness install, and what one should I buy? Thanks!