My suggestion would be to head to the brakes suspension chassis subforum and read up as much as you can on rust repair. Search phrase rust repair in quotations. Also read as much as you can on unibody and chassis stiffness. There are lots of good threads that explain the important structural areas of the datsun unibody, as well as how to reinforce those areas. Looks like you will be doing quite a bit of body repairing. You may want to consider reinforcement during repairs. I hate to tell you but if you have the rust that is visible on the car, you most likely have some very involved rust in other creases and crevices that are going to compromise the safety/integrity of the unibody structure. Not guaranteed mind you, just likely. Welcome to the forum. It is a wealth of information that is invaluable to datsun owners. Keep us updated on any progress you're making by creating a build thread with plenty of photos, we enjoy being part of the build. (That reminds me I need to get some more recent photos up.)