You could pull the entire wiring harness and controller card out intact and sell it for a decent amount if it functions properly. Same with the starter.
I would personally hold on to the second alternator as a spare, but if you wanted to simplify, sell both isolated ground alternators and get one from Autozone with the non-isolated ground.
You could probably get $500 for all of those parts if not a little more.
One more simplification you could do is remove the Starter relay under the dash. Just jump the purple wire to the purple/white wire in the plug (or cut and splice it if you don't care about originality).
To rewire the glow plugs for 12V, disconnect the wire at the resistor on the driver's side and move the wire to the diamond shaped junction block just above the relay. If you remove the entire glow plug wiring harness, run a 12V wire from that same block to the small terminal that had the pink wire. Then run a ground wire from the other small terminal to your switch, and then the other side of the switch to ground.
To make the Wait light function might take a little doing without the card, but the simplest way would be to try splicing a wire from the switch (same side as from the relay) to the dark blue wire in the small plug under the dash that you disconnected the whole glow plug harness from.
You might also have to put 12V to the pink/black wire but I think that it already has the power running to the light and that small plug at the same time.
Later,
Joe