Sometimes the airfares from the US to the major Scandinavian cities are considerable less than those to AMS and CDG. Three or four years ago I planned a two-week trip to Paris but booked MSP-CPH-MSP, with connections in AMS on the outbound and CDG on the return. IIRC, the fare difference was around $800, half of which bought me a rail pass. I enjoyed a couple of days in Copenhagen, then took the train, my favorite kind of transportation, to and from Paris. I probably could have saved more with budget flights, but the train travel was part of the fun.