IMHO, rust above the windshield and the door jambs, is the proverbial, "kiss of death". The problem with rust in thease areas, is not the rust-thru, but the rust you can not see. The best method to eradicate the rust, is to remove the top, by drilling out the spot-welds around the perimeter drip rail, followed by removal of the top cap. By doing so, you can address the rust issues, that have not manifested itself as actual rust-thru.
If the floor boards, kick panels, rockers, cab corners, A-pillars & cab supports are rust, as well, you may be better off finding a donor cab.
