If you are going in late June then it is likely that the mosquitos will be out and about - for those who are not immune to these beasts they are an horrendous plague in Finland and in Lapland in particular because they attack 24 hours a day from first hatching throughout until it gets too cold. October might be getting cold enough to be clear of mossies. Geographically, Finland is unspectacular, rather flat and featureless but that does not mean it is unattractive but Lapland has perhaps the most features and woodland is far less dense. There are interesting museums to see if the weather is not co-operating and you can even go gold prospecting (dig, sluice and pan) - if you are thorough then you stand a good chance of finding some (we found more than just a few specs, although not commercial quantities). Unfortunately I can't remember the place names for these activities but any half-decent Finnish travel agent should be able to tell you. In June you will be able to see the midnight sun if you cross the arctic circle and even if you don't, there will be no darkness at all in Rovaniemi.