Slovenia is beautiful, the area around Lake Bled is really nice, Ljubljana is nice for a couple of days. When I was there 4 years ago, the Tourist offices had lists of people who rented out rooms in their house, which was nice , and at that time was 10-15 euro for a room.
The caves at Postojna (somewhere en route from Ljubljana to Trieste) are well worth it, absolutely huge & Unesco listed. The food wasn't great, they're fond of pizza & pasta. You could easily spend 2 weeks travelling around Slovenia.