Spent today scraping undercoating and stripping paint off the driver's rear fender. Not as caved-in as the right side, but certainly repeatedly hammered.
Driver's side looks to be in better shape. I'll only have to repair the flange, not fabricate a whole new one. Interestingly, the right side of the whole truck is the rustiest.
I'm finding very inconsistent primer throughout the truck. In most places there IS primer, but in others there is clearly zero primer under the paint.