Third Bulgarian Empire

Has anyone done the achievement The Tsar's New Clothes? (restoring the Third Bulgarian Empire)

It is insanely hard to fight and win a 4 front war against Serbia, Greece, Romania AND Turkey, but I managed to do it in a year. But the proclamation of the Empire requires you to win the war in 150 days!

Does anyone have any tips on how to speedrun the 4th Balkan War? The fact that you only have a year from game start to prepare makes it even more difficult, there isn't really that much wiggle room for strats before the war.