Croatian Islands...Pitvice Lakes

I am in Zagreb.  Thinking of bussing (if bikes are allowed on bus) to Pitvice Lakes in Croatia. Reading online looks like some good trails and I want to see the waterfalls.  Any tips on this area (I am hoping to camp, there seems to be a couple spots).  Will one night and a full day and half be enough? And I want to get to the coast of Croatia - any tips, routes (flat as possible) to go? Or should I just try the bus!  Where should one start/end on the coast to start cycling on the islands?   I am eventually making my way to Italy.