What about if the USA decides to land in Greece instead of Italy in 1943? That could lead to the USA reaching moving into Bulgaria and Yugoslavia rather quickly. I see Bulgaria, faced with actual invasion, surrendering quickly if the UK and USA move into it--they were not that big on the whole Axis alliance. The Allied Drive into Yugoslavia could make things interesting. While it could initially offer a great opportunity to screw over the German armies present, it could also prove to be a massive headache for the Allies.
By 1944, you might have the allies trying to move into Southern Romania and Croatia. This would prove more difficult, as the Croats supported the Axis powers to some degree. Romania would probably rather choose the allies than the Soviets, but that might not be workable with large German armies in the area. And Behind Romania, you've got the Soviet Union. The Soviets are still going to demand a piece of Europe--but it will probably be a Finnish and Polish piece instead of a Eastern European one. Romania gets divided (or maybe the Soviets annex their part of the territory?)
I'm not sure how this would proceed after this happens.