We've just come back from a fantastic holiday, staying 2n in Venice, 5n in Slovenia (Bled) and 7n in Croatia (Rovinj) before flying back from Venice (orig planned to fly to and from Ljubljana but direct flights from UK were cancelled). We absolutely loved the whole trip, especially the combination of city, lakes/mountains and beach. Our favourite place was Bled and could have stayed longer there, but we really enjoyed the variety we experienced throughout the trip.
We visited Ljubljana and thought it was lovely, but it was quite small and we were all really glad we had spent 2n in Venice instead. The drive up from Venice to Bled was fantastic too, with amazing scenery.
Rovinj is a lovely town and we had a great sunset boat trip which was a fantastic way to end the holiday. We had originally booked a hotel in Porec for our 2nd week, but when we got there it was v busy and full of kids, and Porec was crowded a bit tacky in the evening (although nice when we visited in the day time) so we left the hotel and rented a villa just outside Rovinj which was much better for us.