I don'tknow what would cause that hole near the driver side headlight, but the car doesn't look all that bad. It doesn't look to rusted out or dented from what the pic shows. http://seattle.craigslist.org/tac/cto/3488931161.html
I'm not sure about that hole either, maybe started out as a rust repair? This one looks plenty restorable though, and not a bad price I think.
Actually pretty common rust areas in those years of Mercs and Fords. There was no real way to keep tire kick up debris out of the front H/L areas once filled up inside there. I have had many solid cars with only having H/L area rust issues in the past.
These cars did not have inner fenders, so what ever was kicked up by the tires landed all over the place, trapping water against the metal. After, of course, the grit had removed all trace of paint and rust proofing. Dodge Aspens didn't get inner fenders until 1980. Darts and Valiants never did.