Koh Phi Phi
Zagreb: Zagreb-Plitvice-Split by public bus. Easy or bad idea?
I don't think there is a line on entrance, and there are few entrances. You will have enough time to see Plitvice Lakes National Park and travel to Split in the evening.
Croatia: Where must I go in Croatia?
Umag is not so nice. Better go to Rovinj. Or island Hvar and Brac , you can easily travel by ferry from Split.
Rijeka: Getting from Rijeka Airport to Ljubljana on a Sunday?
Zagreb: safety and nightlife
it is a very safe city, night life not so exiting, but has a good bars and cafes.
Zagreb: Which is the best way to travel between Zagreb and Budapest?