1399-1821 Switzerland. No expansion. No vassals. No alliances.
Basically played it through as a survival challenge, to turn Switzerland into a relatively neutral armed camp that nobody wanted to mess with. Nobody ended up declaring war on me, though I did participate in several wars - including two against Austria.
It was difficult at times to hold myself to my self-imposed restrictions. No grain provinces mean no Grain Depot, and no port connected to Bern meant my trade was restricted to Europe. Early on, when I could at best eke out 30k-ish troops, France and Austria made me really nervous. I built a CoT after the MRs switched to Administrative.
I started a few trade wars to help build up my Military Tradition so I could keep running a level 5/6 Army Organizer, Commandant, and Sergeant Major General as my advisers. I ended finding a better technique for building up my Tradition - rebel hunting. I became the mercenary rebel hunter of Europe and the Middle East, just give me Military Access and I would sweep them away.
It helped finding a large country that was suffering a high revolt risk. I started out doing a lot of hunting in France, before moving on to Georgia and Russia. Helped out my relations quite a bit too.
Austria was quite the bully towards the end of the game. I ended up guaranteeing both Georgia and Russia to discourage Austria from continued expansion in their direction. They tested me once by attacking Georgia, and got their nose bloodied for their trouble. They did get off light, though, since it didn't make me war leader and Georgia settled for a white peace by the time I cut Austria's army in half.
My other war against Austria was one I started, so I could briefly take Tirol in order to enact the Gold Standard decision - then sell the province off the next day.
Fun country notes:
The Netherlands was going strong about 20-30 years ago. Then La Plata (which apparently includes Madagascar) revolted, and Austria decided to give the Dutch a beatdown, forcing them to release Brabant and taking some provinces in Scandanavia.
Brazil in West Africa, with a couple provinces in Bolivia thrown in for good measure.
Quebec revolted in Quebec, aside from its capitol which was the Turks Islands. Looks like Finland took most of it back.
Haiti actually in Haiti.
Siena and Genoa migrated to the New World.
"Trebizondian Pattani"
"British Colombia"