Well if you're anywhere the rain and flooding areas we hear about... a good top would be on my list
These cars were prone to premature rust. Floors,especially behind the wheels and in the rear behind the seats. If you can pull the carpet and have a close look, poke with a screwdriver from below might help. Rocker panels below the doors can be replaced easily but the inner panels is structural and should be looked at. Shock towers are also a point of contention with rusty cars. If the owner has a garage queen, these issues likely won't be there, but check anyway. How are the electrics? everything work? Fuel injected or carb car? Last service, if unknown, you will be changing the timing belt and flex disk to give yourself a peace of mind.
Good luck