Still chugging along, bit by bit.
I managed to find a fender, mostly rust free (although advertised as rust free) in North Carolina. $150 and a 9 hour road trip on a Saturday with my oldest son.
For reference, here's the old one where it mounts to the body.
And here's the new one.
The rest of it was flawless outside of some failing clearcoat, but the tops of the fastener recess feature were gone and there was some section that I ended up cutting out and replacing as the metal had rusted a bit thinner. Sorry, no pics of the process, but here's the fender after sanding, priming (outside) and sealing (inside). I decided to try out Miracle Paint as I was running empty on POR-15.