So, I have all of the background stuff for the war of German unification ready, I just need to finish one more image.
Before I move on to the actual war, though, I want to figure out the situation in all of eastern Europe prior to the war (so I can better predict the events). Mainly, I want to figure out the Balkans, as we have yet to touch the region and it may end up being essential to Russian operations against Austria.
Serbia:
So, first of all, if TTL the Napoleonic Wars go on for longer and Austria is seen as a collaborative state and is thus attacked, Serbian revolutionaries would flee to Russia rather than Austria as the First Serbian Uprising ended as OTL's Napoleonic wars were stagnating (during Napoelon's first exile). This means that they would have to pass through more Ottoman land before escaping, making the death rate higher. This is particularly important because of one man. The leader of the first Serbian uprising and progenitor of Serbia's OTL royal family: Karađorđe Petrović.
IOTL he escaped to Austria, was arrested at the border, but the Austrians refused to hand him over to the Turks, he was sent to Russia, lived in Bessarabia for a while. The second Serbian revolt, led by a rival nobleman, Miloš Obrenović, was a resounding success. Karađorđe was not permitted by the Russians to participate, so he secretly returned after the revolt to instigate a pan-Balkan revolution against the Ottomans, organized by a Greek nationalist group. He was betrayed by a close friend who let him stay on his land but then had him killed on Obrenović's orders and his head was sent to Constantinople as a gift for the Sultan.
TTL Austria avoids the whole extradition fiasco with the Ottomans, Karađorđe either dies on the way to Russia, meaning his eldest son Aleksandar (future prince of Serbia) and his other children would likely be captured and possibly killed by the Ottomans, or he gets to Russia. With the prolonged Napoleonic wars still going, Karađorđe might settle deeper in Russia, as the border would not be a safe home for his family. He may move to St. Petersburg. From there, he would definitely want to return to Serbia, but the sneaking back to Serbia thing would be a lot harder, so he would likely stay in Russia until around 1840 when his family was allowed to return IOTL. His sons would probably still serve in the Russian army.
So either Karađorđe dies and later dynastic conflict does not affect Serbia or he lives longer. Either way, Russo-Serbian relations are even better TTL and the Austrians would not have nearly as much support as they did in early OTL Serbia, as they would not get the reputation boost from refusing to hand over Serbian leaders to Turkey. This would be a problem for the Austrians when they go to war with Russia, so they might try to occupy strategically important locations at the start of the war. They might occupy the Ottoman exclave of Belgrade to strengthen their defense against a Russian or Russian-supported attack through Serbia, though they would need the Ottomans permission for this or risk war. An excuse might be made, like preventing a Russian attack, but the Ottomans wouldn't want to start a war with Russia either, so....
Romania:
Another area of interest here is Romania. The region wouldn't change much until the Spring of Nations. They would have their own revolutions IOTL around the same time as the rest of Europe. The goals would be independence for Moldavia, Transylvania and Wallachia. Russia's response to the TTL equivalent of these could determine their geopolitical position at the start of the war with Austria. From the post Napoleonic map, I see that the Ottomans have given autonomy to the Romanian states. Is the assumption here that they already revolted or were they already autonomous OTL and I'm just forgetting about it?
Either way, the Russians might try to get into Austria through Romania or fund revolutionaries in Transylvania.
I doubt Greece will have any role in this war even if the Russians and Austrians do get involved in the Balkans.
With all these foreign armies passing through their land, the Ottomans might get mad or might be too afraid to stop them. Or maybe none of my speculation makes sense and I'm just rambling again.
To sum it up (if you don't want to read all of that):
Sorry for rambling on. I just felt that I need to know roughly what would have changed in each part of Europe before getting to work on a war between 4 of its largest powers.
So:
How much stuff would happen in the Balkans? What has happened there so far, and how might it affect the situation during this war? This war doesn't focus on the region, but it could be an important battleground between the Russians and the Austrians. Otherwise, their rivalry, boosted by the war, might urge them both to try and eat up as much land in the weak Ottoman empire as they could. I'm definitely seeing a second Russo Turkish war breaking out after the Russo-German alliance wins this war, and presumably the Russians take a break from fighting, because constant war never did anyone any good but that doesn't effect my current work.
Before I move on to the actual war, though, I want to figure out the situation in all of eastern Europe prior to the war (so I can better predict the events). Mainly, I want to figure out the Balkans, as we have yet to touch the region and it may end up being essential to Russian operations against Austria.
Serbia:
So, first of all, if TTL the Napoleonic Wars go on for longer and Austria is seen as a collaborative state and is thus attacked, Serbian revolutionaries would flee to Russia rather than Austria as the First Serbian Uprising ended as OTL's Napoleonic wars were stagnating (during Napoelon's first exile). This means that they would have to pass through more Ottoman land before escaping, making the death rate higher. This is particularly important because of one man. The leader of the first Serbian uprising and progenitor of Serbia's OTL royal family: Karađorđe Petrović.
IOTL he escaped to Austria, was arrested at the border, but the Austrians refused to hand him over to the Turks, he was sent to Russia, lived in Bessarabia for a while. The second Serbian revolt, led by a rival nobleman, Miloš Obrenović, was a resounding success. Karađorđe was not permitted by the Russians to participate, so he secretly returned after the revolt to instigate a pan-Balkan revolution against the Ottomans, organized by a Greek nationalist group. He was betrayed by a close friend who let him stay on his land but then had him killed on Obrenović's orders and his head was sent to Constantinople as a gift for the Sultan.
TTL Austria avoids the whole extradition fiasco with the Ottomans, Karađorđe either dies on the way to Russia, meaning his eldest son Aleksandar (future prince of Serbia) and his other children would likely be captured and possibly killed by the Ottomans, or he gets to Russia. With the prolonged Napoleonic wars still going, Karađorđe might settle deeper in Russia, as the border would not be a safe home for his family. He may move to St. Petersburg. From there, he would definitely want to return to Serbia, but the sneaking back to Serbia thing would be a lot harder, so he would likely stay in Russia until around 1840 when his family was allowed to return IOTL. His sons would probably still serve in the Russian army.
So either Karađorđe dies and later dynastic conflict does not affect Serbia or he lives longer. Either way, Russo-Serbian relations are even better TTL and the Austrians would not have nearly as much support as they did in early OTL Serbia, as they would not get the reputation boost from refusing to hand over Serbian leaders to Turkey. This would be a problem for the Austrians when they go to war with Russia, so they might try to occupy strategically important locations at the start of the war. They might occupy the Ottoman exclave of Belgrade to strengthen their defense against a Russian or Russian-supported attack through Serbia, though they would need the Ottomans permission for this or risk war. An excuse might be made, like preventing a Russian attack, but the Ottomans wouldn't want to start a war with Russia either, so....
Romania:
Another area of interest here is Romania. The region wouldn't change much until the Spring of Nations. They would have their own revolutions IOTL around the same time as the rest of Europe. The goals would be independence for Moldavia, Transylvania and Wallachia. Russia's response to the TTL equivalent of these could determine their geopolitical position at the start of the war with Austria. From the post Napoleonic map, I see that the Ottomans have given autonomy to the Romanian states. Is the assumption here that they already revolted or were they already autonomous OTL and I'm just forgetting about it?
Either way, the Russians might try to get into Austria through Romania or fund revolutionaries in Transylvania.
I doubt Greece will have any role in this war even if the Russians and Austrians do get involved in the Balkans.
With all these foreign armies passing through their land, the Ottomans might get mad or might be too afraid to stop them. Or maybe none of my speculation makes sense and I'm just rambling again.
To sum it up (if you don't want to read all of that):
Sorry for rambling on. I just felt that I need to know roughly what would have changed in each part of Europe before getting to work on a war between 4 of its largest powers.
So:
How much stuff would happen in the Balkans? What has happened there so far, and how might it affect the situation during this war? This war doesn't focus on the region, but it could be an important battleground between the Russians and the Austrians. Otherwise, their rivalry, boosted by the war, might urge them both to try and eat up as much land in the weak Ottoman empire as they could. I'm definitely seeing a second Russo Turkish war breaking out after the Russo-German alliance wins this war, and presumably the Russians take a break from fighting, because constant war never did anyone any good but that doesn't effect my current work.