Need HELP in BAD WAY!
REAL REAL TOUGH
Could be the regulator was not working or miswired, and was causing massive overcharging. Did you notice the battery puking/ bubbling/ smelling?
Other than that, a MASSIVE short. (Could be right in the alternator.)
What I'd do is yank out the harnesses that are affected, and as you go, not "what has been hot." MAKE NOTES Then untape them, looking for which wires have burned to which wires.
Check the ammeter that it has not shorted to something up under the dash
The "ignition run" circuit, which comes from the key, and supplies ignition, choke, alternator field, regulator IGN terminal, and maybe idle solenoid is usually dark blue. IT IS NOT FUSED
You have a shop manual? There's a 72 you can download on this site.