Jeff,
Any boat that old is a potential nightmare, be it Grady White, Bayliner, whatever. Improper care and maintenance can do a boat in, even if the most previous owner took really good care of it. If the boat was mistreated at any point in its history, the resulting insult could fester over subsequent years of excellent care and result in very bad things, like rotted out transom, leaking fuel tank requiring the floor to be pulled up, crapped-up lower/upper hull joint, sensitive wiring, etc., etc.
Consider the $2,500 a down-payment. The question you need to answer for yourself is how much more money are you willing to throw at it. It is not a question of if, but when and how much? Some boats that old are not worth taking for free, if you need to drop $3K on a new transom, $2k on a new floor and stringers, and another $1k on a rebuilt rubrail area.
That doesn't even factor in the engine. Maybe the engine is a gem. Maybe it drops a cylinder your 3rd time out and guess what, nobody has a rebuilt block for it so you are into a new/used outboard.
$15k later, you probably have a real nice boat
and
Not trying to scare you off, just give the boat a very, very thorough inspection. Tote up all the "little things" that need to be fixed. They add up very quickly. That $40 bilge pump is more like $240 when you factor in the munged-up wiring, no float switch, undersized hose and outlet, etc., etc. Need to replace any canvas or vinyl? Multiply by 3 whatever guesstimate the seller gives you on what it will cost to fix.
BTW, don't rely solely on a marine shop survey -- the last time I tried that I ended up throwing $2k at an engine that the shop assured me was in "excellent" condition.