Cape Dory 30
I think you''ve ended up arriving at your own answer. You seem clear that a CD 30 Ketch is narrow, slow, tender and hobbyhorses...and altho'' you haven''t said it explicitly, the rig is unsuitable for the setting (ketch vs. lake). OTOH you''ve ID''d some good reasons why - for you, for now - it''s a choice that makes sense. The most convincing of your reasons, I think, is "this boat looks good. It seems very hard to find a boat that looks this good...."
Altho'' your description of the financial end of things sounds good, the one thing I don''t hear you acknowledging is the fact that, some day, you will end up needing to sell the boat near/on the same lake. My impression is that the ''lake'' is in fact a smaller, perhaps man-made one (vs. e.g. Lake Michigan)...and so you too will be looking to sell a boat to a buyer population for which it will seem an odd purchase. That will affect your resale price just as it is apparently influencing your purchase cost.
Good luck and don''t get too wound up in how some of us describe a given boat''s sailing characteristics. They may be one critical criterion but hardly the only one. Just take to heart the descriptions you''ve been given here, which I think are pretty accurate and which you seem to have accepted, as well.