I did the Slovenia in One Day Tour. From Ljubljana we went to Bled and visited the island in the lake (this was extra as it is not part of the tour). After having some Slovenian delicacies by the lake, we went onto Castle Predjama and the on to the Postojna Caves which were the highpoint of the tour. Ivana was the tour guide and she really did an excellent job. If you want to see the main attractions of Slovenia in a day, I would definitely recommend it.