Originally Posted by i_timmers

For the scope of rust damage you were up against, he did a fantastic job on your sedan! I am originally from Long Island, New York(I reside in Arizona now) and I have seen my share of "Cancer" on cars. Did you ever locate all your drain holes on that car to keep them clear of debris? This is probably one of the most important things you can do to preserve the car along with a thorough washing of the undercarriage and wheelwells keeping them free of buildup. Another good tip if your storing it for winters, disconnect your battery. This will remove a magnetic field from the car, it won't attract moisture causing it to rust.
There was a friend of mine who purchased a 68 Camaro SS RS convertable from the original owner. That was the key, keeping the body nearly rust free for 25+ years prior to my friend purchasing it.

Good luck!