74 Duster won't start

The issues in no particular order

battery terminals. battery terminals. battery terminals

battery cables

battery

starter relay

connections at the starter relay

connections at the bulkhead connector

connections at the ignition switch

ignition switch

wiring and connections from starter relay to starter

wiring and connections from starter relay to starter

connections. connections connections

starter.

I admit freely that "intermittent" is a giant PITA and can be tough to find.

Sometimes, you have to 'rig' things, and if a screwdriver works for two weeks, then, well.............

It might be that if the relay was bad (rusty, burned contacts, etc) that when you wiggled the shift linkage, or slammed the door, that "made" the connection

I WOULD TAKE THE OLD RELAY apart and inspect it!!!!!