I own a 1978 C&C 34'' here in the Seattle area and use it for cruising and club racing. The 34 is a relatively tender boat and in order for it to go fast one must keep it on it''s feet but is a good cruiser and if racing against boats of similar displacement can do very well. I think the main issue as far as offshore vs coastal cruising is the capacity of water and fuel. we have taken the boat around Vancouver island which on the outside is offshore. Another factor of offshore vs coastal is it''s limit of positive stability of 116° (capsize ratio)I think they like most offshore boats to have higher limits. Subscribe to the C&C list on Sailnet. They have a wealth of info and advice. The website www.cncphotoalbum.com is also a good resource.
Good luck and if you have specicifc questions contact me off the list.