Post war the Federation might be providing the Cardassians something like the Marshall Plan that America did with Europe after the second world war. Some Cardassians would resent the "foreign aid" coming from the Federation. And the various non-Cardassian aliens that are supervising it's organization and distribution. Cardassians being fairly xenophobic.
I really fail to see how a Cardassian ship, with a Federation officer on board, would have particular interesting stories. With the Union in such dire straits, are they going to be off exploring the galaxy? Or just puttering around inside the devastated Union?