Bosnia basicaly doesn't have ports (besides Neum, which is not realy practical), so either Albania / Montenegro / Croatia. Most likely Albania - Kosovo - Serbia route, since it's already established heroin smuggling route.

Most likely Montenegro -> Serbia. Much easier, then going through two other countries, and Montenegro has issues (both election, and previous corruption problems).

Last time I passed through Montenegro I got stoped by two cops and they straight out asked me money (they wanted 20 euros for each), so they didn't suspend my license. (and yes, they were slavic/montenegrins and not Albanians)

I was going 64 khm/h on a 60km/h zone. They are corrupt as hell.

> Most likely Albania - Kosovo - Serbia route, since it's already established heroin smuggling route.

I assume this would require the smuggler to either be a Serbian or Kosovo citizen, or make a handover to a local person in Kosovo? A citizen of a third country cannot enter Serbia after entering Kosovo from a third country. The Serbian authorities will deny you entry and tell you to go back and enter into Serbia from one of the other countries bordering it.

Well that's how it works in theory. In practice the smuggler can sneak across the border or bribe the authorities, just like in every other country.

Most likely Montenegro, since it is easy to move to serbia from there (plus there are serbians that live there), and the country is going through some election transition period, so things might slip through easily.