This car needs a RESTORATION!!! Nothing short of that. Not trying to hurt your sale, but very few peaple are ready for this kind of work, even fewer on this site. The hard reality is that people who like this kind of cars will spend some more $$$$ to get a clean original (or restored) one.
Unless you want to do a quick Bondo job, you WILL need to cut and weld new metal in. Most rubber parts will need to be replaced, and so are all fluid lines, gas tank, fuel pump, brakes, bushings, and so much more.
Good luck with the sale, but you might as well clean it up and store it INSIDE for another 10-20 years!