Norrland is one of three major regions in Sweden. Norrland encompasses two-thirds of the country's surface and about one-sixth of its population. Most of the major national parks in Sweden are located in the Northern parts of Norrland. The region is characterized by forests, mountains, rivers, mines, a harsh winter climate, long distances, left-wing attitudes, as well as university towns with young populations.
Connex  runs daily trans between Göteborg and Narvik, Norway with several stops, including Stockholm, Uppsala and many along Norrland. Sleeper accomodations are available. Reservations are required to use the Eurail Pass. Price for the full trip was around 450SEK on a simple seat as of 2006, and the journey totaled more than 24h. Stockholm - Abisko (for starting Kungsleden) was about 17h.
The city of Kiruna can be accessed by plane and is located close to the Kungsleden trail.
The connex train can be used for some connexions inside Norrland. There are also some bus services, e.g. from Kiruna to Nikkaluokta, close to the Kebnekaise fjällstation. Car rental will often be the only solution for getting to some remote places, assuming there even is a road to get there. In winter, snowmobiles are very popular, and cross-country skiing as well as dogsled are other options.