Hey, 

my name is Teresa and I am planning my DiscoverEU trip through East Europe right now. 
At the end of April I want to start in Prague and then finish my trip in Athens in the end of May. 
Here are the places I want to visit. 

Prague, Warsaw, Budapest, Belgrad, Bukarest, Sofia, Thessaloniki and Athens.

Unfortunately, I am unsure, because of the Ukrainian war, if it is safe and possible to travel and find trains that connect these places. 

Any answer or recommendation would be very kind and helpful. 

Thank you