I've found the windows - especially quarter glass - to be a PITA.
Another is the '68-'69 dash switch panel & troubleshooting/replacing those switches.
Been through the re-work hassles, too.
If it was all easy, I'd be fine with that; but the satisfaction of getting things corrected might not be as good.
What's intriguing to me is how some cars are easy, and some fight all the way through.
Oh those 68-69 switch panels are a real mfer. I tried to forget those for sure. Deeply rewarding to get everything going, probably why every car seems to have stuff not working.
