Vinyl dyed it black, then changed out the connectors on the retractable cord reel.
Drilled and cut a 40-tooth front sprocket.
Installed the cord reel in the now empty slot in the battery rack.
And after a great deal of annoyance trying to fix the cut-off relay for the charger, it's working.
The bike can now be charged from the built-in extension cord or the gas tank plug receptacle.
I'm just waiting for my replacement drive chain to come in the mail.
The series-parallel switching relays are working as expected.