I have a ’74 Tradesman I pulled out of a junkyard for a project. The body is in near perfect condition. I have a similar issue. and am not in the skill area of welding. My rust issue, instead of holes, there is an elongated rust hole in my door panel. It measures about 8 inches long with a gap of about 1/4 inch. I have heard using a technique using fiberglass repair behind the damaged area, after removing rust, and then fill and sand etc. Is this a correct method or do I approach it in a different direction? I hope this posted in the correct area, I am new to the forum world.