In Mark's reply you have the link to the national scenic routes; we plan to cover 1 of them and most of another.
We haven't completed this trip yet, but will be driving from Bergen on May 25 to arrive in Oslo on May 30. Our plan is to drive north from Bergen to visit family in Dale in Sunnfjord and then drive along a portion of the Gaularfjellet National Scenic route to Solvorn to spend a night. From there we're driving along another national scenic route, Sognefjellet, to Fossbergom/Lom and spending a night. We're hoping the snow has been cleared on the roads by these dates. From there we're staying in Lillehammer 2 nights before flying out of Oslo.
We also considered a return flight from Bergen to some area further north along the coast for a couple days before setting out from Bergen by car, but timing became an issue for us once we found out we will connect with family north of Bergen.