The Whitehorse and Yukon .....I think is a must. you can book online at the RR site or through the ship. If through the ship you get picked up at dock side and there is a three block walk if you do it through the RR. Two separate pieces of train are then joined for up and back. Coming back you are delivered to the dock.
If you do the return trip on the train you go up on one side and down on the other. The seats reverse and everyone changes side with a little prompting from staf. There is outside viewing between cars and I believe an open car on some trains.
If you book via the tain you are in the cars closer to the engine and going up you may experience some fumes especially if you are in the car right behind the engine. BUT going down you are last and the views are much better. At the top the engines switch around the train and reverses for the return trip.
There are other tours. combining longer rides and buses using the hwy for return or visa versa. Check out their website.
Again I loved it. Great views