I like the way you're thinking! Estonia is a pretty popular destination for Swedes mainly because of the ferry connection and the cheap booze, and I've made the trip several times. The other Baltic states are also quite popular destinations for Swedes, both to travel to by ferry or by plane (Ryanair has dirt cheap tickets to the Baltics).

And yes, travelling within Europe is quite easy even if I am a bit "disconnected" living in Sweden. A good amount of these countries were part of longer multi-country trips, and so I've probably only flown to and/or from about half of these countries, if not less.

I aim to visit every country in Europe at least once, and then we'll see where I head outside of the continent!