I would look for new panels to be fair.
Apart from the tailgate, that looks like a nice little job for me. Sand it down, rust treatment, filler, sand, primer, filler, sand, primer, sand, paint, sand, laquer.
Damn - looked in my diary and it's too far for me to get there with a trailer anytime soon. I'm all over the place towing things over the next few weeks, in fact down your way on Friday, but already got something on the back.
Someone will snap it up and mend it. If not, if it's still around when life calms down I'd certainly be interested.