What time of the year are we talking about?
It also depends of course greatly on your interests.

I agree coastal Norway is definately an option. Very nice

If you start in Copenhagen (I am biased but I believe it is a great city) then consider either flying direct to Bergen or sail to Oslo from Copenhagen (night ferry/cruise). The Copenhagen-Oslo drive is not that spectacular.

As an alternative consider the small islands south of Fynen as well (Langeland, Ærø, Tåssinge and bunch of really small islands). Very laid back and very nice for both relaxing, hiking, cycling, sailing og just having a good time. A bit off the beaten track.
http://www.visitsydfyn.dk/internatio.../om-sydfyn.htm
http://www.aeroe.dk/