Planning a trip to Europe?

I am interested in planning a trip to Europe for a couple years from now, and I at least want to go to Finland, Norway, and Denmark. I want to see the Northern lights, and the mountains in Norway. I was interested in staying at the Igloo Village in Finland, but I think it will be out of my budget. And I want to travel by train for a portion of the trip. What is the best route to go for all of this?