12 days Bergen to Stockholm

We will be flying to Bergen from the US arriving March 10th, then have about 12 days before we meet up with our son and his family in Stockholm and travel on to Copenhagen and Germany. We will be traveling by train with backpacks. What would be our best route (it doesn’t need to be direct), to explore as much as we can on our way. We love nature, scenic train rides, history, architecture, local culture. While we enjoy it, we aren’t huge on museums and art. We would love any suggestions we should consider as we plan. TIA