62 Chevy-
You might be going a little (or a lot) overboard. Fix the rust that you have. If you are really concerned about stopping rust make sure that all drain holes are kept clean, and have a good rust inhibiting service (Ziebart's) spray you interior panels. They drill holes into inaccessible panels and spray retardant, then cap off the panel. Every five years or so, have them retreat the truck.
What I'm really trying to say is don't throw money and time away trying to search for perfection in stomping out rust. Take reasonable precaustions, but don't completely cut apart your truck to make sure you get all the rust. You'll end up with a truck scattered all over your available garage space. Then you'll give up on putting it back together, and you'll sell it to someone else or take it to the junkyard - eventually. Also makes females extremely untractable.
If you really want to permanently eliminate rust and money is no object - you could always get a fiberglass cab and/or other panels for your truck. US BodySource makes them ($4000). I guarantee that it'll never rust....
