One of the most beautiful, culturally diverse and just plain fascinating regions I have been to is the Eastern European countries of the Balkan Peninsula. What is difficult is that transportation is limited. The roads are good, but few trains and rather ratty looking buses. I don’t drive on vacation, just against my religion. But I do enjoy driving on vacation and in this area I can afford to sit back and let someone else do the driving. But, I appreciate your taste and your desire to drive.
So, while it isnt any of the three options you listed, it is what I would do if I drove and if I wanted to revisit some of my favorite places (many discovered on fishing trips). I sort of offer this almost as jest as my taste is really off the wall. But it gave me a few minutes to relive some of my favorite places.
If you were to do this crazy trip you would want to make a few more stops than this, but some of the highlights would be
Podgorica, no nights
Mojkovac, Montenegro at least one night, as many as three if you are into trout. I know this stunning resort sort of place in the mountains.
Žabljak, Montenegro, well just outside, on the Tara River gorge. Stunning. Ride the zip line. At least a night, and again, more if you are into trout.
Ostrog Monastery, Montenegro for a stop to see the monastery built into the side of a cliff.
Budva, Montenegro and excellent coastal town. A night or two. While I didn’t add it to the route, a day or two south at Stari Bar and / or Ulcinj would be wonderful. These are two towns you will never forget.
Perast, Montenegro, yup, I skipped Kotor. Yes, stop if you want, but it’s nothing compared to Dubrovnik. Perast is picture perfect little town on the bay. Really beautiful
Dubrovnik, Croatia. Two nights tops. Its beautiful but its also tourist hell.
Mostar and Split. I haven’t been to either.
Jajce, BiH, beautiful country. Wonderful sights. Good trout.
Sarajevo, BiH, here is a town that is an enigma. I cant explain it. I both loved it and hated it. One of the more emotionally moving places I have ever been. Not to be missed.
Belgrade, Serbia; a must for one or two nights. Not a beautiful place, but the place drips with modern history.
Novi Sad, Serbia; beautiful and where I would spend the second night after Belgrade
Timisoara; some of the best of Romania is in and near here.
Budapest; no better place to rest and unwind before heading home.