In your post regarding Slovenia you mentioned using Venice as the gateway. We did this same thing several years ago, taking a catamaran, the Prince of Venice, across the Adriatic to Portoroz, then overnighting in Piran just to the north. We found Piran to be a quaint little seaside town which was a great transition from Italy into Slovenia. This part of Istria was under Venetian dominion for centuries in the Middle Ages and its architecture underscores this strong relationship between the two areas.
Before catching a bus to Ljubljana from Portoroz (a much more commercial and less charming tourist town than Piran) we were able to buy some produce at the small open air market in Piran. A great way to begin interacting with the Slovenes (Dober dan!). Plus, I can still remember the flavors of the finest pears I've ever eaten. Also, while having breakfast that morning at our seaside hotel we noticed several enthusiastic open water swimmers getting their morning exercise in the clear waters of the Adriatic. If your daughter's a swimmer this might be of interest to her.
In Ljubljana, where we only spent one day, we took in the castle with its good views of the surrounding city. I do recall there was a wedding party in progress while we were there and that the graphic design on the entrance passes was a wonderful art nouveau-stylized dragon, the symbol of Ljubljana. At the time I thought the design would have been great for a t-shirt but, alas, I could not find one. Another good vantage point for a view is the Neboticnik Terasa café on the top floor of the Art Deco skyscraper at the corner of Slovenska cesta and Stefanova ulica downtown. While there, if you're daring you can sample zganje, a brandy (eau-de-vie) distilled from plums. Or if you prefer a beer ask for pivo.
Lake Bled was absolutely beautiful, as were the surrounding Julian Alps. I fully intend to return in order to ski at Vogel and Kranjska Gora, maybe the winter of 2003-2004 (if my subtle hints to my wife work out). While in Lake Bled be sure and rent a row boat to visit the Baroque church on the island. Ringing the bell at the church is an absolute must. If your daughter enjoys mountain biking she'll have no problem finding a rental to cruise along the vast array of trails around the lake and the surrounding mountains.
Finally, another area to consider visiting is the Karst region with its allure of limestone caves. I regret not having visited the Skocjan Caves and Predjama Castle. Lipica is in this area which is between the coast and Ljubljana. As good a reason as any for us to return to lovely Slovenia.
Have a good trip, John in San Diego