Started a brand new game as King Björn Ironside with the following goals:
1. Unify and Create the Scandanavian Empire
2. Reform Germanic Paganism
3. Sacrifice the Pope to Odin
4. Kick Ass! Not hard to do as a Viking!
Well, I managed to become King of Sweden as Björn, and conquer most of Finland to boot. I nearly managed to reform Germanic Pagansim, but my chancellor failed to fabricate a claim on the final site I needed for 14 years! (14% chance per year. I had 59% MA too!)
Björn's son managed to subjugate Norway and get the final holy site, only for moral authority to have dropped to 1%! (-20 from expired conquest bonuses, -24 from failed Holy Wars against Catholics in Denmark. The AI sucks sometimes.) After that I let the Pope convert us because being unreformed pagan would really hurt my plan to switch to feudalism, our powerful neighbors were Catholic, and we were already rapidly converting regardless of my attempts to stop it.
That ruler died half a year after starting the conversion process and I was then forced to use a -300 prestige, not very good son to fight off one civil war and one Suosmensko uprising. (Managed to do it because we let the Teutonic Order set up a castle in one of my counties.) Now I've switched to Feudalism (saved just before in case it's a mistake(not ironman)) and am starting to use looted gold from the Mediterranean to build up our own holdings. My long-term plan is to make Scandanavia an economic and military powerhouse by improving all most of it's empty land. I'm also going to modify the succession laws so that I can keep all of my titles.
Now that I'm starting the process of improving this land, I'm starting to wonder if I should've stayed tribal longer. It seems I need a lot more gold, but I am getting quite a lot by raiding Genoa and Venice, as well as some select coasts and islands. Do any feudal improvements require prestige? This is my first time really fooling with building.
Edit: Just checked the CKII wiki and realized that I can create a a merchant republic within my empire, for a huge economy boost. Just need to do a bit of scheming, looting, and charity to do so.