As an ex-Maritimer, exiled to Uppity Canada a quarter century ago - I would suggest you give some serious thought to looking at Ontario boats. They are freshwater boats, hence a 1975 on Lake Ontario is likely to be in better shape than a 1975 that has been in salt water all its life. Had boats down there and up here, and it's a pretty substantial difference. Also - you're going to pay a premium for boats down there, simply because there are fewer boats, hence supply-demand ratio is not as favourable.
I would not recommend the Tanzer/CS/Abbot 22's for the ocean, as they are pretty light and tend to bob around too much when the sea gets up. If you can find a CS 30 in decent condition, you'll be pretty happy with the boat as they are confortable, strongly built, and quite fast (for a cruiser).
C&C 25's are definitely decent boats, probably the smallest that you'd want if you plan to do any kind of cruising at all - even then you're going to need to be careful.
Good Luck !
CS 27's are also an option. They are pretty numerous up here. You can probably pick up a decent one under 20k and then ship it down east, and still save money versus buying it there. Check out this website:
http://www.boatforsale.net