The Line-X thing is great for trucks that see a lot of abuse to the exterior paint from rocks, sand, etc...Western trucks, trucks that see a lot of gravel road use, etc. The problem is Line-X does nothing to prevent rusting from the inside out, which in the Salt provinces, is the biggest issue. Rocker panels, door bottoms, etc are still going to rot from the inside out just like they always have.
Line-X, then regular oil spray treatments would be the best way to protect a truck you really wanted to keep together.