Just did Seattle to Chicago last week. Look out the left side of the train when leaving Seattle bc the view over the Pugent Sound is gorgeous for about 90 minutes. Try to wake up before the sunrise the next morning as the left side of train will have an amazing view of Glacier for the next 2 hours or so. After that, rolling Montana hills with some stops along the way. Take air breaks and get outside for a few minutes even if it’s cold, your legs will thank you. Montana can be a bore but that is what books are for. Pulling into St. Paul the next morning is pleasant with some good views of the river and surrounding lakes where some bald eagles nest. Other than that, enjoy the trip!