preserving new vehicle?

I use Krown on all of my vehicles. Unfortunately it's an annual thing at $149 (cdn). But my daily driver is a 1999 Camry with no rust and a 2007 1500 Ram with no rust. My next project is my dad's 1987 Ram 150 that he bought new. That truck has seen everything Canadian winters can throw at it.......It has a couple of pin holes in the driver side floor pan. It too was treated.