Since I have a boat of this vintage (1967) and one of the few models Jeff_H seems to moderately like (Tartan 27') I'll chime in again.
Some things to watch out for on this vintage of boat are:
- chain plates, water intrusion rots wood core and weakens chain plate
- soft decks, again from water intrusion. Decks were usually made with wood cores
- engine age/hours
- rigging age and condition
Even though Jeff_H mentioned the model of sailboat I have I can tell you that I would not take it to Hawai'i (or Bermuda for that matter) in its current condition. Before I headed out to anywhere like that I would want to:
- re-build all chain plates
- replace all standing rigging
- re-power with a newer diesel (current A4 is 42 years old)
- re-core the few soft sections on my decks
And that is just the short list that does not include extra gear for blue water (radar, ssb/sat phone, life raft, EPIRB ...) useage.
That said, our boat was well maintained by the previous owners and is in good shape for a boat her age and just fine for near coastal use. We also got lucky that the PO had already bought himself a larger boat (Irwin 32') and was tired of paying 2 yard fees so we paid $4k.
I agree with you that how well the boat has been kept up is key to older boats. They do not even maintain book values for boats older then 1975 as each boat is unique in how it was maintained.
What model it is determines it's best usage. A Catalina 27' is always a C27, right?
check out this link: The Ultimate Catalina 27