I would appreciate suggestions for a 3 week tour of all 4 Scandinavian countries in December. I would like to spend time in urban and the most beautiful outskirts of each region. I would like to ski and ice skate while there and get a feel for authentic Scandinavia.
Thanks much.

being picky but Finland is not really Scandinavian but hey they sort of go together. December is dark (no really dark) in some parts it is night time all the time. Most people don't live in that part so if you want daylight stay south.

I'd look at Bergen, Oslo, Lillihammer, Malmo, Copenhagen, Stockholm as the main places, if there is no snow (and it is possible with Climate Change) then go north to somewhere like Levi.

Iceland is the fourth Scandanavian country.