Dionysius, why dont you make the scenario starting in the 1340s when the Turks have just captured their first european outposts?
Now it is set just before they conquered the last remnants of their adversaries. Doesnt make much sense.
A hundred years earlier the region was a mosaic of little late-feudal countries and "empires" in constant intrigue and shifting wars and alliances. A ripe and intriguing terrain for a scenario of conquest for the Ottomans! Byzantium had two emperors fighting each other, Bulgaria has split in two tsardoms and several despotates, Serbia was for a short while united and strong but there were various independent despots in Macedonia, Thrace or Epirus who paid homage to nobody despite their greek or slavic ethnicity.
Often a christian country had to admit Ottoman suzerainty to save its skin for a few more decades, and to volunteer to join the turkish armies in battles against its christian brothers.
Would be also challenging to play as one of the christian states and attempt to organise a union^ to stop the invaders - in reality there very few such attempts and all of them were defeated.
What do you think?
^although politically the region was very divided, culturally it was more shared than ever before, with free flow across the borders. XIVth century was the cultural boom for us (named Palaiologian pre-renaissance). For example, many slavic clerics would graduate in greek academias, often greek monks would know slavic language, books were constantly translated both ways, etc.
As for maps and historical information - there is plenty on internet! Use wikipedia - for that period it is fairly unbiased. More maps you can find with google.
The political situation was very complex at that time, if you get confused you can always ask here for help. Apparently there is plenty of locals who have studied their history.
In any case, thanks for the hard work! Greetings to Ireland!