Interior vs Body Work

Budget is probably the deciding factor. The interior can be redone for cheaper and more quickly. Body work will likely cost a good bit more and take more time. The point about eventually having to remove the interior to do the body right is on the money. If you can afford it, do the body first. Seats can be redone fairly cheap and easy if you do it yourself. Rust will destroy the car, cracks in the seat or dash will not.