Here Are The TWO BIGGIES...
Eliminate the pass through the firewall alternator charge lead wire. Wire direct to battery isolation device and use a voltmeter not an ammeter for the chassis.
Chrysler took LSD when they designed the voltage regulator circuit. Learn how to install a Bosch style RELAY and use it to power BOTH the alternator field ignition feed wire and the termnal that feeds the top of the connector at the voltage regulator.
The 1980's REVISED SQUAREBACK MoPar alternator is a plug n play for your 60 amp. Choose the 78 amp model.
Use 6 wire TRAILER wire cable under the chassis to the rear. eBay truck 7 way connector junction box for distribution ease. Get a 1/8" POP RIVET GUN to redo junk clearance lights don't try to use screws. LED markers and tail lights are the way to go. Expensive but a bottle of DeOxit D100 cleaner works miracles on bad connections. anything else is a bad joke.