Utah

My old 1983 Ram had hardly any rust on it, my 206k mile 1993 Chevy K2500 also hardly has any rust on it.

The 83' ram had truck bed liner on the bottom part of the panels. (which is not feasible on cars, except maybe for inside the wheel wells, interior floors and some of the underbody parts)

The big thing that I noticed that helps alot is wash all that salt coating off whenever the roads get clear enough and hasn't snowed for awhile.

EDIT: Also make sure the paint isn't chipped and have bare metal/primer exposed, if it does use those little spot repair paint brushes to at least cover up the exposed metal/primer (temporary fix only!) until you can fix it properly.