I don't think it is possible to predict anything involving the trains or the roads right now. Did you see Croatia last night? Three days ago traveling the roads in Croatia was a guaranteed okay thing to do. Today?
For those who read here often you know I enjoy Central Europe and especially Budapest. We come 2.5 times a year so I am always looking for new experiences. We have done Bulgaria, Romania, Slovakia, Austria, Czech Rep, etc. This trip, in progress now, was fly into Dubrovnik: a magnificent setting that I am glad I experienced although, like Venice it is a town that has become a museum. Still, for a day and a half it was magnificent. Then overland to the Bay of Kotor. (2 hours and on a road that is well off the refuge route). The Bay is astoundingly beautiful. Even found time for a little fishing. Escaped the tourists by staying in Perast where we dined on the edge of the bay as great sailing ships sailed past. Then on to Kotor the miniature walled city twin of Dubrovnik, that was still a living city. Finally into Titograd for a night before an Air Serbia flight to Belgrade (60 euro). All the road time from Dubrovnik to Titograd amounted to about 4 hours and much of it was with spectacular views and great towns and villages. What a trip! Wish we had gone years earlier. The big surprise was Belgrade. Loved it and returning soon. Then another 60 euro flight to Budapest where I now sit. Of course I can spend the next 10 days here with no chance of boredom.
So think outside the box. Romania, Bulgaria, Slovakia are all great destinations, cheap to reach by plane.