If you are just trying to get the motor to run... then the black to red sounds like a good plan.
Or... pop the ignition cover off and trace the wire from the insulated side off the points up through the wiring harness.. if you run that one straight to the coil it will run but you won't have a switch.
Otherwise... I think the wire from the points goes up to the ign switch and then down to the coil... so you should be able to trace both of them.
Then use a volt meter to rest for comntinuity at the switch.