If you want something to learn fabrication skills on, not expecting to ever get any of the money back that you pour into it, then go ahead and dig in. It's the perfect kind of car to learn on. But if you think it will be worth anything later, you are going to be disappointed. Patched up '59 fourdoors are not an easy sell. If you decide to do some work, take small bites like just doing foot long sections of the roof at a time. Keep it running if at all possible. That way you can have still have some fun instead of it totally turning into a pile of work.