Balkans trip 2019

I plan to do a trip in Balkans for severan months. The exact route will change depending on the people I will meet on the road, I know when I stard i don't know when I end ...  Here is a first estiation, I will try to keep it up to date :

9/10 : Arrival at Budapest

Mid October :  Szeged - Belgrade

?? : Belgrade - Krusevac

?? : Krusevac - Skopje

?? : Skopje - Sofia (trying to avoid mountains...)

?? : Sofia - Plovdiv

?? : Plovdiv - Istanbul (if I have time...)