With advice from my neighbor, think I tracked down the short.
First thing, made a tool. Previous owner had the wiper in the headlight hole, headlight below.
The important button to get the headlight knob out.
Headlight switch had the red wire spliced in, but is a dead end.
No idea what this switch supposed to be for, it was mounted in the wiper hole. Yellow wire spliced for this.
I know this is the plug for the heater control, because I removed it. But no idea why the yellow wire was spliced in.
Mystery wire.
Because of the way the wiring harness is made up, I couldn't relocate the wiper switch to the right side of the panel. The wiper switch was one of the first new parts I got, so it's in. Had to Dremel the hole bigger so it would fit.
I really want to repaint the dash, someday.
Since the floor is rusted junk, and I don't plan to weld in new metal, I ground off the gas pedal pegs. I'm thinking of using Eastwood rust repair product, and something like a bed liner over the floor, better than getting cheap rubber junk that will self-destruct in a few years.

Eastwood:
https://www.eastwood.com/paints/rust-solutions.html