Hi Sarah, sorry it took me so long to get back to you! My dad was able to give me the names of two great places in Dubrovnik, called Orsan and Nautika. He said that the Italian place was no longer there. Best islands to visit are Hvar (very popular). Otherwise the Plitvice area we don't really know. It is supposed to be amazing though. Hope they enjoy it...
Keep me posted on the summer plans!