Rental car and hotel? Ahead of time, absolutely.
Yes ahead of time. Train prices go up and up and up as it gets closer to the date. AAA rate requires something like at least 10 days out, but of course it would have been cheaper 2 months before.
Starts in south downtown Seattle and it ends near BC Stadium in Vancouver; a short taxi ride to the port.
Cascades is the only train that goes on the Seattle/Vancouver route!
OK, so...
People often fly into Seattle because it's cheaper than flying into Vancouver. But then they realize that there are extra costs and time to this.
Seatac airport is a solid half hour in light traffic to the train station in downtown Seattle. As far as I know there aren't flights landing early enough at Seatac to get to downtown in time to check in for the morning train. If you fly in the day of the cruise, now you can't make the early train. And if you take the late train well you've already missed the ship by the time you're on the late train.
So now you've added at least one day on at the beginning of the trip. You either fly in, get a hotel in the Seattle area, then catch the early train up on the day of your cruise...or you fly in, take the late train up, and stay overnight in Vancouver.
Taking the train up the day of the cruise can be done BUT there are issues with Amtrak! Amtrak doesn't own the rails; freight does. So if there are many freight trains on the tracks in front of you, you have last priority. If there's a problem on the tracks, you're stuck. If there's a landslide at any point between Seattle and Vancouver that goes onto the tracks or threatens them, they have a policy that the tracks are closed for 72 hours. This means that you get to go on a bus. The train has periods of time where it goes along the coast and it's just gorgeous. You can see bald eagles and trees and many parts of the route are amazing. If you end up on a bus, you're on I-5. NOwhere near the coast. Maybe you'll see eagles, but generally not. The time we were put on a bus (when I learned of the 72 hour thing) they stopped every 40 minutes or so for bathroom and smoke breaks. It was raining. As a lung-sensitive person, having smokey damp people getting back on the bus was nearly unbearable. No food, no water. UGH.
So if you take the chance to take the train on the day of the cruise, you could still miss that boat. I haven't heard of this happened here, but it *could*.
So if you're risk-adverse but want to spend time in Seattle AND Vancouver, you've now added 2 nights on. Fly in, hotel in the Seattle area, train in the morning, hotel in Vancouver, THEN the cruise.
If I recall the train back to Seattle is rather early as well, so you can't disembark and take that in the morning. So you've got the day to fill, then you have the late train, and then you have few flights out of Seattle IF there are any that you would be there early enough to check in for. So that's a hotel at the end of the trip as well.
I *love* the train. It pales in comparison to trains in other countries (in terms of ease and timeliness...Amtrak runs later with every stop it makes), but it's still lovely.
But I would run all the numbers, look at my vacation time, and my budget for the whole trip, before deciding to fly into Seattle and take the train because it's cheaper.