Replaced all the marker light bulbs as well as the driving light bulbs, since they're all the same bulb anyway. I originally started to diagnose a dim driver's front marker light but then found that every bulb except the passenger front side marker was bad. Replaced them all and now everything lights up as it should. Previous owner wasn't even aware those red side markers lit up, they've been dead for so long! Feels pretty good.
Also picked up a pair of headlights. The old ones are all originals and fogged like crazy, so since I have to pull a headlight motor tomorrow anyway I figured, may as well replace both headlights while I'm at it. If weather and everything holds up, I'll be trying to do both the headlight repairs and a valve cover gasket replacement. We'll see how it goes.