Well, I've finally gotten around to checking on some of these things. Much to my surprise, the connections on the headlight and even the switch look super clean, no rust at all. Connections were tight, no frayed cables or anything like that. I disconnected all the wires, looked them over well, then re-connected them. All are clean and shiny.
However, I did find that the wires running under the rear fender were frayed. So I picked up some 14 gauge wire from a local hardware store and snipped out the frayed section of wire and spliced in a new wire, then tucked it back under the rear fender. I really thought this would fix it, but sadly I still have no lights. I can still fire it up with no issues, but oddly all 3 of my lights aren't working now (head, tail, brake).
I don't think I did a shit job splicing the cable, but I guess that might be an issue. I'm gonna try again and see if that helps.
Oh.. and I did look at the bulb. The filament appears to be in good order (not broken or loose)... but I think I might try a new bulb anyway in the off-chance that'll fix it.
Any other feedback on this?