I also drive my 67 birds in the winter..Dry roads with the tell tale white dry salt still there..20 years, absolutely no rust or bodywork on the car. The "I won't drive my car in winter because of salt and rust" is another BS theory.
As long as the roads are dry, and you wash the car as you would in summer, there is no problem. Now when you drive in slush roads, and the slush cakes up under rockers and fenderwells and frame, there is your rust problem. I enjoy driving my pristine original bird on Christmas and New Years, granted the roads are dry. 20 years, winter and summer driving, went through a frame off, complete strip of exterior paint, and NO rust through or surface rust.