Tips on inspecting/buying a 40 year old car?

Man that looks just like a 73 Scamp I bought about 10 years ago. Before you read any further, it is definitely NOT it. Anyway, everything checked out. There was very little bondo in the normal areas. Good looking little car. It was not until I rode behind it that I found the problem. The rear end was not lined up with the front. Somebody did a good job covering up that little fact. Ugggggg! I have not bought another old car since, but if I ever do, I am going to take a ride behind it if I get a chance.