300 miles in a day in Europe is easy. Sustained 300 miles every day, for weeks and months, is very hard.

While that's a decent loop, you've got a huge gap there between Finland and the Balkans. There's definitely plenty to see there - assuming you don't want to mess with Russian and Belarussian visas, you would be going through the Baltic States (fairly interesting) through Poland (probably via Warsaw and Krakow, the latter definitely worthwhile), then Slovakia (specifically the High Tatras - feel free to skip Bratislava), into Hungary (Budapest is a must). From there I'd turn east into Romania (Cluj-Napoca, Turda Salt Mine, the Transfagarasan and Transalpina roads, really lots of nice mountain and forest roads in the national parks, Brasov and Bran Castle definitely, Bucharest by preference) into Bulgaria (stop by Moto Camp, say hi to Graham Field), and on to Istanbul.

From there (having paid the exorbitant toll for the Europe-Asia bridge, but of course you have to do it!), into Greece - maybe head south, maybe not - then Macedonia (I hear Lake Orhid is very nice), Albania (bunkers everywhere!) and Montenegro (try to time it for the HUMM meet there), maybe see the European Federal District of Kosovo on the way but head for Dubrovnik and up the coast, get a Bosnia and Herzegovina stamp in your passport with that little chunk of coastline, then keep going up through Split and Zadar. Into Slovenia for the Vrsic Pass, possibly into the wonderful SS-roads of the Dolomites, over the Carnic Alps into Austria and the Grossglockner. Through Innsbruck and Feldkirch, cross Liechtenstein off your list, into Switzerland for the Furka-Grimsel-Sustenpass triangle, and down to the Lake Maggiore/Como area. Then west again via Gran Paradiso to Chamonix, pick up the Route des Grandes Alpes all the way down to Monaco. Follow the Riviera coastline to the Pyrenees, check out Andorra. Do a circuit of Iberia and end up back in Santander/Bilbao for the ferry home (or, if it's running by that time, the direct Santander-Ireland ferry).

Hell, now I want to do that!