More parts arrived. Bunch of stuff from Small Parts Inc. I seem to have forgotten to order the M8 threaded rod. It can wait.
Started soldering the Power/Comms board. The 12- and 2-pin headers are tough to insert. Bent a couple pins. Should be OK.
Turns out the board only uses the 12V line from a PC power supply. Had a 12V 3A supply lying around. Wired it up. Looks good. Light comes on. 78L05 produces 5v.