When you do decide to do a good job, I would consider sandblasting all of the old paint and bodywork off of the car. You will want to be sure that you have put an end to any rusting or bad workmanship. Find a company that has done car bodies before. Tell them to get in to all of the pitted areas. Follow immediately with a self etching primer, then with a urethane that will seal it, and you can do bodywork on it. If you do it right, and take proper care of it, the paint and bodywork can last almost indefinitely.