Croatia & adriatic coast , caught my fancy just last year ,thanks to tempting images on social media like FB,instagram etc . For me ,its always been a bit confusing ,to distinguish the geographical cluster of tiny countries in east Europe . Names like Slovenia(always had jumbled up Slovenia & Slovekia to be same !) ,Croatia, Montenegro ,Bosnia etc never make it to "must visit" list if one were to plan a Euro trip from India/ASia & the only fleeting references i recollect were from newscolumns ,largely connected with the conflicts from Yugoslovia-Bosnia days. Thanks to Bond & other spy movies, could identify few cities like Zagreb ,but 99% of the places were new to me ,even a month back. But the online images of the places were spell bounding ,too good to be true ,seemed straight out of photoshop studios. Finally planned this trip in about a week's time in May . What started with a plan just to cover Dubrovnik ,thanks to "Game of Thrones" ,more & more research, led me to new places like Bay of Kotor, Lake bled ,Pltivice etc. 3-4 days iternary extended to almost 13 days.
Weatherwise, travel in May in Europe ,can always be tricky & conditions can vary drastically. Thanks to weather gods, we were blessed with pleasant weather throughout, just ducking past the rain gods in few places.May-June being shoulder months can be an ideal escape from the onslaught of peak tourist seasons of July/Aug.
My travel internary : FRankfurt-> Ljubljana->Lade Bled->Zagreb->Plitivce National Park->split ,Vis, various islands along adriatic(HVar,Brac,etc) ->Dubrovnik->Kotor(Montonegro)->Ljubljana->frankfurt.
Hiring a car in Slovenia/Croatia can way too cheaper than hiring in Germany. I had my apprehensions(border control/GPS /etc) of driving in unknown terrritory ,but it was no different than driving in Germany or any other central European countries. I was amazed by the smooth highway network(especially A1) in Croatia ,which seemed pretty new & way better than autobahns of Germany ,thanks to almost non-existent traffic on highways .