there is no easy way to prevent rust,the metal needs to be clean and rust free and yes it is time consuming and boring .I use a very coarse wet and dry (used dry) and rainex rustbuster and then fishoil and then a good primer and a top coat .I have a HT kingswood that i have owned for 34 years and i treated inside the doors and boot and i havent touched it in about 30 years and it was left outside and used as a daily driver until about 5 years ago and still all good