Figure I'll double post and give a bit of an update on my saga as well. Turns out the leaking left valve cover was due to two stripped out bolts. To add to the headache, a previous owner had botched rethreading with heli-coils, necessitating different rethreads. Ended up drilling out and using EZ-LOK steel inserts. Truly a wonderful product. Reassembled, and no more leak! Forks and front brakes are now rebuilt as well, and the front half of the bike is pretty well good to go. Took it out for a quick test jaunt yesterday, and it's definitely on the up and up. After having been neglected for so long, it's nice to be bringing this ol' Spot back up to snuff. Next steps are to disassemble and rebuild the rear brake system, service the drive shaft & FD, and service the carbs, as it's currently stupid slow to warm up to idle. Need to bed in the front brakes too, as they're currently quite grabby.