Finnmarksvidda, in Norwegian Lapland, is a vast highland plateau with many lakes, rivers and mosquitoes. With an average height of 300 - 400 meters, and a few mountains only, this is real Tundra. The lower valleys are overgrown with beautiful and light birch wood. On the higher elevations one has to deal with stiff bushes, marsh, and many streams. On the whole, hiking is easy.
From mid April onwards, there is daylight around the clock. A great time for a ski tour. The walking season is best at the end of the summer, from August onwards. The billions of mosquitoes are still happy at work in August. In september they are less annoying, but then you might come across the first night frost allready. Do not expect reindeer herds: in summer they have migrated far north. Do expect a good catch though: the lakes and rivers are full of fish.
Walking is excellent in Finnmarksvidda. The area offers several types of cabins. The so-called mountain huts, or Fjellstue, are run by Sami families. They offer simple but good accomodation. There are several self-service huts in the area, where you can buy some food. And finally you will find quite a number of unstaffed huts.
What to take along? Insect repellent of course, boots instead of shoes, a stick to keep your balance when wading the rivers, a sleeping bag and good rainwear.
The most obvious walk starts in the Sami village of Karaksjok and runs northwest to Alta. This trail will cost you 4 to 5 days to finish. There are some variations to consider. From Alta take the bus to Narvik and then the train to Stockholm.