Not a big fan of ac on boats, especially small ones,, unless you plan on spending an awful lot of time at the dock.
As to C&C's, generally, the 29 is a good boat to start with. My general impression is the best old C&C's are the odd numbers (29, 33, 35). I just cant recall whether is is cored or not. I'd rather have a solid hull from the early 70s than a cored hull from the late 70s or early 80s.
There's a very good website called something like cncphotoalbum.org which would be a very good place to ask questions. It has original brochures and a lot of articles. Good luck.