Buying an old boat

I am buying a 1981 Nautique and want to know what I should be looking at in order to be moderately informed regarding the "realistic" condition of the boat. We are buying the boat for sentimental reasons as it belonged to my father in-law, but I just want to have a general idea if the boat has serious issues i.e stringers. What I do know....I know the boat has 500 hrs on the original motor, the transmission was recently rebuilt as well as having all of the seals replaced. I also know that the boat has been trailered and used in fresh water only for at least the last 8 years. Beyond that it's a crap shoot! Any guidance or advice would be greatly appreciated!