You should have some customizing shops in your area that do undercoating and rust prevention. I have a Ziebarts here in NY. They undercoated the bottom of my truck with a tar like substance and they spray another compound in the doors, fenders, and so on. It helps fight against all the salt they use in NY. I have done this to all my vehicles. Keeping your truck washed and clean is one of the best ways to prevent rust also.