I drove the whole coastline in Croatia from Porec to Dubrovnik and i liked it.
Dubrovnik is nice with a big castle, Split and Zadar also. And there are some more nice places i have to look up.
But i was there in summer. I find the older people al little "cloesd" and quiet.
I know somebody who fought in Dubrovnik and lost friends there.
He don't want to live in Dubrovnik anymore, he lives in South America now.
Maybe you can rent a car and drive to Dubrovnik and Zadar. The roads (toll) are good, not much traffic.
I went there cause people told me in Greece a lot of old architecture was destroyed by earthquakes. In Croatia a lot of old buildings are still there. And that seems right.
my pictures:
http://www.traveltube.nl/view-album/9/vakantie-kroatië