The company Innlandstrafikk (bus number 150) has several departures between Elverum and Trysil. See departure sites here: entur.no
You can also buy tickets from many places in Norway to Elverum on this site.
Elverum has railway connection, and you can reach Elverum by train (Elverum Skysstasjon), and continue to Trysil by bus. Train timetable on www.vy.no
Trysilekspressen, the Trysil Express bus, runs between Oslo and Trysil every day of the year. Travel time is about 3 hours. Boarding takes place at Oslo Bus Terminal and Oslo Airport Gardermoen, with several stops along the way. The bus stops at the Tourist Center, Radisson Blu, Radisson Blu Mountain Resort, Trysil Høyfjellssenter and the bus station in Trysil during the winter season.
Find you travel plan and book your bus ticket here
Bus from Copenhagen, Malmö, Gothenburg and Karlstad
Swebus has several daily departures between Copenhagen, Malmö, Gothenburg, Karlstad and Oslo. Find your travel plan on www.swe.se
The buses from Swebus go to Oslo Bus Terminal.
Continue to Trysil with Trysilekspressen (the Trysil Express Bus). See above for timetables.
Transfer to and from the airport
Sälen Buss / Trysil Buss is happy to help you with transfers to and from Scandinavian Mountains Airport. Transfer must be booked in advance.
Transfers from Scandinavian Mountains Airport must be pre-booked here.
Sweden +46 280 203 00 or firstname.lastname@example.org