Tonight I replaced the ignition electrical switch. I pulled both the cluster and the lower panel & crossbar. That gave me terrific access, allowing one hand to reach from underneath while the other hand through the top. There are still a lot of wiring harnesses to deal with, but the access sure made things a lot easier.

The old switch did not show any external signs of wear or corrosion. However, with the new switch, the lights are brighter, the wipers run faster, the seat heater is warmer, and the headlights do not dim when I hit the brakes. It's quite the upgrade for my ride.

Thanks again for the pointers and advice. Much appreciated.