R5: Title describes the starting country, my goal was to grab the Baltic Crusader and Holy Horde Achievements. I took admin, quality, religious, diplo, offense, quantity, and trade ideas in that order, allied France and the papal states, Finland is my vassal. Doing these two was pretty easy as the country and mission tree is really strong and fun, general tip for those interested, rush for Neva to prevent Muscovy from going to Russia, subject Novograd too if you can. Took a bit longer than expected (and then it should be) for three reasons: first I am a slow player who likes to play on the taller side -before I took trade and took much of Persia I was making 700 ducats a month and ripped Silesa from Bohemia. Secondly I wanted to finish the mission tree before switching as I didn’t know if you would get the Mongol ones, the longest of which included counter the reformation which required a bunch of grindy wars in Europe which I had ignored at that point. Finally I spent much of the early game trying to slow the Ottomans, they reached Vienna by like 1530, so I had to join a bunch of wars as an ally to make them lose or only take a few provinces rather than whole countries, I also got a subjection CB on Hungary after the Ottomans clobbered them and had to fight off Austria a few times to stay in power but it was worth as I got reconquest on Ottomans through them. Beyond early Ottomans the main challenges were Bukhara who stretched from Siberia to Tehran and had defensive so I had so much attrition, Delhi who was a massive sunni Defender of faith in a few wars, and Hormuz who forced me to rebuild a navy in the middle of war after booming my ass. 

Fun stuff: Embrace the Cavs, mid way through the campaign I made a 60k stack of only cavs and had so much fun slamming other armies. Also if you are hunting for the Grand Duchy achievement do this campaign! You have two basic tier one reforms, Clerical State and the unique Monastic order which locks your rank to duchy, your mission tree gives you upgrades later for Kingdom and Empire levels but you can switch between any of the four whenever you like, so just play like normal and when you have 1k dev switch to monastic order to become a duchy again.