Not a whole lot more to test. The wiring from the alternator to the VR is part of the light harness, and there is also an alternator harness that goes to the alternator from the starter solenoid. If you're ambitious, you can start unwrapping the tape and examine the light harness from the VR area and follow wiring around the radiator support to the alternator area. If you find a splice of some sort, make sure it is connecting the right colored wires together and that any exposed wire strands are kept apart by electrical tape and such.
I'm 98% confident your VR is shot, but it may be your wiring that contributed to that condition.