Electric issues on a 1966 Plymouth valiant please help

My girlfriend just pulled a 67 valiant out of barn where it was parked in 1974. The car has the original slant 6 and automatic The engine turns if we jump the starter with a screwdriver but not when we try the key. So far we have done new battery, battery cable on both sides and a coil. Old coil was cracked. All the fuses are new. Can someone please point us in the right direction to get the key working?
Thank you for taking the time.

check the ballest resistor The white retangle on the firewall.. the center could be burnt . or the voltage regulator.

The ballast resistor is for the ignition circuit, not the starting circuit.
The starting circuit consists of the ignition switch, the starter relay (which requires a signal from the ignition switch and a ground), and the starter. You have eliminated the starter as a major source by jumping across the starter relay. You are now down to the relay itself, the positive source for activating the relay from the ignition switch, and the ground.
The signal from the switch will require a test light or volt meter to verify. Have the switch on (unplug the ballast resistor to keep voltage from the ignition circuit and burning points). Will take two people to verify. One to rotate the switch, the other to probe for voltage at the starter relay input signal. If this voltage is good, the next thing is grounds.
The ground comes through the neutral safety switch. You may unplug the negative source and jump to ground to verify if the starter relay is functioning. If the neutral safety switch is the issue, this will allow you to bypass. If the relay is the issue, the relay will not energize and activate the starter.
http://www.mymopar.com/index.php?pid=27 is the source of the wiring diagram.