Not compatible with the Mayfair version, then! Another expansion I won't be buying in that case, because I'm not going back and paying for a whole new copy of the base game, Seafarers and C&K!
You don't really need the full frame. Using the German editions I cannot say anything about hex size compatibility, but the incompatibilities are fairly minimal. And there should be a frame adapter kit.
While I usually play almost everything with C&K, I don't feel the urge to do so with this expansion.