We will be on a cruise and have one day in Kristiansand, Norway. What is the best way to see the highlights of this city, foot, organized tour, private car?
Hope you mean Kristiansand (S) and not Kristiansund (N).
If Kristiansand (S): On a nice day I would just do a walk along the coastal promenade to Bystranda Park and a loop back through th town.
You could also walk up the hill to the WWII Vestre batteri which offers a nice outlook above the coast.