My wife and I will be cruising the European capitals (Copenhagen, Stockholm, Heksinki, St Petersburg) next June. Since Oslo will not be part of our cruise itinerary, we plan to tour Oslo and the Norweigian environs following the cruise. We will have three days before returning home. Would appreciate suugestions on how we might cover a reasonable amount of the country. We would particularly like to include Kristiansand as my wife's maternal grandmother was born there. Rent a car? Take the train?