First I'd charge the battery & then if no lights/accessories & wont crank then either the fusible link or bulkhead or ammeter, one of those 3 went open. Plus likely the reg (electromechanical?) fried & may have opened the blue wire with tracer that goes from the ign switch to the 'ign' side of the reg then it T's there & feeds the coil positive primary so if that is open it'd crank but no start. I would cut that blue wire with tracer at the ign switch as it may be dead shorted to ground somewhere along its' length since it was passing too much currrent that melted its' insulation. Jump 12V to the 'ign" side of a new reg to power the system & get you going. Holler how it goes