I don't do 'sit in the sun and broil', or 'walk up sodding great big hills'.
I like something in between - warm and sunny, a bit of culture, a bit of fresh air (preferably with birds), some good food and cheap wine, friendly natives.
yes to all that, though the beaches aren't sandy till you get well down south. Dubrovnik and Split are excellent historic towns (Split is actually built inside a Roman emperor's palace); Rovinj and Piran are small towns that look like mini-Venices (they were Venetian once) Pula has a Roman amphitheatre; Zagreb's a busy city. Lots and lots of islands you can...