JH,
I say you should keep it and learn on it. I'm doing the same thing with my REALLY rough '64 Dart GT. Your's looks to be only rust, while mine is rust and impact damage. At least mine doesn't have rust through on the cowl or firewall.
Make the Harbor Freight run. Don't forget a 3" pnuematic cutoff tool and I've had good luck with the inexpensive pnuematic body saw. Then stop at the metal supply shop for a sheet or some scraps of 18ga or 16ga. I've been searching Craigslist for a bead roller, but you can make ribs with ball peen hammers anyhow.
Now as far as rust repair, neither your car, nor mine, has any rust issues at all, at least in comparison to this car:
http://www.forabodiesonly.com/mopar/showthread.php?t=106974
I was wondering why I should even bother with the Dart I have. Being in FL now, I am SO missing living on the west coast with clean sheetmetal. I probably wouldn't have even bothered looking at this Dart for parts when I was living in Oregon.
But, same thing, I'm getting experience and learning, virtually for free. I already have all the tools, and a van body I'm cutting up for sheet metal. I borrowed a pressure pot type sandblaster and need to buy primer.
Go for it man!
Mike in FL