Entrance to Boka Kotorska
If you are driving south from Croatia, Herceg-Novi, along with neighboring Igalo will be the first major town you will reach. From Herceg-Novi you can drive all around the Bay of Kotor (Boka Kotorska).
The drive takes some time, but it shouldn't be missed. The towns are charming and the scenery is dramatic. Imposing mountains drop directly into the sea. Gasoline and deisel in Montenegro were extremely inexpensive - at least to this Californian.
With low prices like you see in Montenegro, you won't mind at all filling up your gas tank, even if you are filling up two tanks.
Discovering I had a full tank of gas is one of my fondest memories...

dubrovnik
clocktower gate
View to the sea
The church of the Archangel Michael