We lived near Piran, and it was amazing. Amazing crystal blue ocean water, old Italian architecture, cheap Italian food on the beach etc. Then the Alps are only a couple of hours away. Lake Bled is one of the most gorgeous places on the planet. Ljubljana has great European charm. Primorska castle is the most unique castle you'll find--built right into the mountain and protected a Robin Hood-character knight.
Lots of fun stuff in Slovenia. Croatia is great in the same way. And they're much more affordable so you can eat out more.