I thought the train stopped for customs and immigration at the border (as did the Adirondack, which we took from Montreal to New York City), but I notice from the schedule that the two trains, unlike the Amtrak buses on the same route, don't stop before they reach the border, so I wondered if one perhaps does through immigration and customs at the Amtrak station and, thus, one needs to allow time for that.

If these procedures are done at the border, how long does it usually take? On the Adirondack, it was quite quick (even when, on the day we went, two passengers were quickly escorted off the train).

Although our destination would be the upper Olympic Peninsula, flying to Vancouver is less than to Seattle. We'd rent a car upon arrival in downtown Seattle, rather than at SeaTac (less variety but lower costs).