Point of No Return

1969 340s Barracuda Fastback, Auto 727 HD, 340, Air Conditioning Survivorish-Fish

Bought the car in 2001. Daily driver for 2-3 years. I always kept her running but she has seen some Colorado winters outdoors. No worries, drove her daily in 2015. Now, the intermittent starting issues have me tearing me hair out...

New ignition switch
New battery cables
Cleaned engine bay bulkhead connector
New Starter
New Starter Relay

... yeah I'm that guy that just throws parts at it cause I'm sure I know what is wrong and am electrically incompetent.

The weird GD thing is, every time I replaced a part she started perfectly for 1-2 weeks then symptoms return.

Today I pulled the engine bay bulkhead connectors and nothing looks badly corroded. No melting of the connector blocks either. ****.. Maybe it is on the cabin-side of the bulkhead connector.

When it doesn't start, starter still clicks, so I assume it is not the Neutral Safety Switch, which I assume would cut off all power to the starter. More like not enough power to starter.

By the monkey tits of Hey-Zeus, I am incompetent... Any sage Mopar advice?

Thanks in advance.