Unless you are extremely knowledgeable (in other words a surveyor yourself) I extremely strongly suggest that you get the boat surveyed by a SAMS or NAMS certified marine surveyor. When you talk about a boat from the Mid-1970''s (the worst period for blister and deck core problems)there are a wide range of posible problems that are likely. At 24 years old the boat may need some combination of blister or deck core repair, keel bolts, engine rebuild or replacement, instruments, standing and running
rigging, upholstery, galley equipment, electrical work,
rigging and bulkhead attachment point repairs, hull to keel joint,rudder and steering gear problems and so on, not to mention aesthetic issues. Any group of these items can easily exceed the purchase price several times over.
While most of these things are easy to detect, most of the really expensive things here are hard to detect if you don''t know what you are doing.
Jeff