Train from Oslo or Bergen
There are daily departures to Gol from Oslo and Bergen. From there, the bus or taxi journey is only 30 minutes.
Hemsedal can be reached by train, aka Bergensbanen, from both Oslo and Bergen. If you travel from Bergen, you will see fjords, mountains and Europe's largest mountain plateau, Hardangervidda. The stretch's highest station is at Finse, 1,222 meters above sea level.
The train stops in Gol, about 30 min from Hemsedal. From here you can take the local bus Brakar route 360 or pre-book a taxi.
The local bus Brakar, route 360, from Gol station, allows you to connect to Hemsedal with a few departures. You can book the full journey by train and bus at vy.no/en or via the Vy-app. Schedule and tickets for the local bus is also available at vy.no/en or via the Vy-app.
Alternative from Oslo - bus VY170
An efficient alternative from Oslo is to cath the bys VY170 that goes from Oslo through Hemsedal. Rad more here: Vy express bus VY170 from Oslo to Hemsedal.