Montenegro is stunning. The gulf of Kotor. Take the road inland from Budva to lake Shkoder. Macedonia is OK but for €50 I would avoid it next time. I found Albania to be of more interest. The mountains in the south were stunning. Indeed there is a lot to see as you head into Northern Greece.
Lake Shkoder: Me out front and Colebatch behind.
another of Lake Shkoder:
The Vikos Gorge in Northern Greece for example
UK Insurers tend not to give out Green cards so you will pay border insurance for most of the non EU Balkan countries except Croatia. As a rough guide and depending on where you cross this is roughly what you'll pay
Bosnia - I crossed on the tiny coastal strip that intersects Croatia and didn't pay anything
Montenegro - €10
Albania - the border guards were distracted by the ladies in the car behind and so again we didn't pay anything
Macedonia - €50
Kosovo - €15
Serbia - they wouldn't let us in because we were arriving from Kosovo
hope this helps
Be warned though you might find dodgy motorcyclists manning the bunkers in Albania