Regarding Finland and depending on what you want to do (and how much time you put into it):
- normal touristy sights to see near your route: cities of Helsinki, Turku and Porvoo have something to offer there
- nice riding plus sights: The
Aland isles and especially
Turku archipelago trail, both situated between Finland and Sweden, are magnificent. The trail will take several days to navigate (lots of small islands with mostly free ferry connections in between), not a lot of daily mileage but splendid scenery. If you go that way, you can combine parts of the two and then continue onwards to Stockholm on board of one of the several ferries that run between Aland and Stockholm.
Mainland Finland has some nice riding too, and the good thing is, it's fairly easy to combine riding with other modes of transportation. Long distance buses carry bikes for a small fee and minimal hassle. With
trains, it's still easy, but bike capacity in newer trains is limited. Advance booking is therefore advisable. If you have the time, you can for example bike from Helsinki to Porvoo (some 60kms), see the sights there and take the vintage
M/S Runeberg ferry back to Helsinki.
Regarding Sweden you will have to plan ahead your transfers towards South, unless you want to ride the whole way. Swedish buses and trains are very tricky in the sense that most do not officially carry bikes except packed as cargo. There are a couple of trains from Stockholm towards Denmark that specifically accept bikes. We saw people (tourists?) take their bikes in the trains nevertheless and get away with it, but those were commuter (shorter distance) trains and I didn't see any train staff during the journey. In long distance trains I suspect you will not be admitted. You can complain to
Swedish Rail. That's what we did, not that I see it changed anything yet.
--J