The number one rule is _not_ to take everything apart then try to put it back together. Many cars meet their end this way, look at " For sale, lost interest " cars on Craigslist. Taking apart is easy / fun/ putting together take lots of work.

You really need to get a handle on body rust first. Rockers on these cars are structural so start there if that is truly the only rust. The rockers will need to be cut and welded in not tapped down and puttied over.

If the shell is too rusty, consider looking for another car and using current one as a parts car.