I would recommend an airplane as a choice of transportation between HKI-ROI. Eh, that's Helsinki and Rovaniemi. Oh well, wise to use abbrevations.
Though, I've done the trip on a train so many times that I probably have grown weary of the any of the positive sides of it.
The sleeping cabins are exactly that, sleeping cabins. They are not ideal for travel while awake. The time being end of June one can of course enjoy the scenery for most of the trip if one desires so. Then again, it is forest, forest, forest, a lake, forest and occasionally town.
If you're heavy sleeper, the cabins are okay, if not, it is kinda terrible. The newer sleeping coaches are nice but it won't help smoothen the tracks.
If you want to socialize the restaurant coach is for that, but again, most people on the night train are there for one beer and then -> Zzzzzzz. So just pub-touring at Rovaniemi can lead to better experience.
Flying is a bit more hassle but at Rovaniemi end you're gonna need to rent a car anyway, so the hassle is about 3,5 € bus fare per person from the center of Helsinki to Helsinki-Vantaa airport.
You can get to Ivalo relatively easy on public transportation but then going the extra 40 km to Inari to visit Siida (the Sami Museum), stopping before Ivalo at Saariselkä etc. come a lot more easier with a car. And, the road between Rovaniemi and Ivalo is essentially one straight line. So it is nice to be able to travel that as fast possible. Just be aware that there are reindeers. That come to the road, on a moment's notice.
There's lots to be done at each of these cities/towns, starting from nature trails around the city of Rovaniemi to Arktikum,
to Rovaniemi Art Museum to the friendly neighbourghood "fell" of Ouninvaara that you can top in around 45 mins starting from any of the city centre's hotels.
Thank you!
