After a bit of research and knowledge from my previous trip to Croatia, I decided I wanted to do this as a rough itinerary:
Ljubljana (had already visited twice – love the city)
Pick up a rental car in Croatia
Istria and hill towns, stay in Rovinj
Zadar
Krka National Park
Sibenik
Kravice Waterfalls in Bosnia
Montenegro – Bay of Kotor
Sarajevo
A few towns in Bosnia: Jajce, Trebinje, Travnik, and Banja Luka most likely
Return the car in Croatia and fly home
But I didn’t commit to stay anywhere except Ljubljana the first night – I decided my stops as I traveled. Here’s what I wound up doing after all was said and done:
Ljubljana – 1 night
Rovinj – 2 nights
Lovran (Kvarner Gulf, near Rijeka) – 1 night
Zadar – 1 night
(Stop in Krka and Sibenik)
Trogir – 1 night
Dubrovnik – 1 night
Kotor – 1 night
Trebinje, BiH – 1 night
Sarajevo – 3 nights
Jajce, BiH – 1 night
Plitvice Lakes – 1 night
Samobor (near Zagreb) – 1 night
Amsterdam (before flying home) – 1 night
I flew from the US (Portland) to and from Amsterdam on Delta Airlines (direct flights) using Alaska Airlines miles. I flew KLM from Amsterdam to Venice the same day I arrived and flew at the end from Zagreb back to Amsterdam then (after an overnight) flew home to Portland. The KLM flight was cheap, only about $150 USD total for the two fights within Europe. (This looked to be the most practical way to get to Ljubljana for me; flying into Zagreb and taking a bus/train would have been another option, but the flights/timing weren’t as good. Flying to Ljubljana directly would have not worked for me on that day from Amsterdam.)
I rented a car for two weeks and drove through Croatia, Montenegro, and Bosnia (see below).
For planning, I used the Rick Steves Croatia/Slovenia book (also covers Sarajevo and a bit of Bosnia) as my primary guidebook. This book has served me well on past trips. I also used the Bradt Bosnia travel guide by Tim Clancy – one of the few (only?) travel guidebooks that covers Bosnia exclusively. The Bradt book was essential for info about towns like Jajce, Travnik, and Trebinje, and his book gave me other ideas of places to stop. I consulted other books such as Lonely Planet’s Croatia guidebook for the parts of Croatia not covered by Rick Steves (e.g. Zadar, Sibenik, Krka National Park). To learn more about the Bosnian War of the 1990s (and the Sarajevo siege) I found numerous great documentaries on YouTube (I mention a few later in the Sarajevo section).