Is there a train from Seward to Vancouver?

Or is flying the only way to return after cruise?

No trains. You can drive, however. Easy way is to fly or take a round trip or b2b cruise.

Virtually everything in Alaska will, at some point, involve either water or air transit.

It is possible to drive to Ak, but it is a long, long way.

Or is flying the only way to return after cruise?

You can drive (but it's a heck of a long way): https://maps.google.com/maps?saddr=Anchorage,+AK,+United+States&daddr=Vancouver,+BC,+Canada&hl=en&sll=37.0625,-95.677068&sspn=51.708931,114.169922&geocode=FQgdpgMdCrQQ9ylBP7MEdpHIVjHjaISnWrp9JQ%3BFaqq7wIdOW6p-CmzT6lD8XOGVDGL84Gb6paRuw&oq=vancouver&t=h&mra=ls&z=5

Thanks for the replies. Our friends want to go on an Alaskan cruise but it stops in Seward. I saw the possiblility of b2b cruises but they mentioned a train. Just checking all the ways.

As others have said, there is no train service. This is convoluted but it is possible to take the Alaska Marine Hwy (ferry service) from Whittier to Prince Rupert, BC where you could catch Canada's VIA rail and eventually end up in Vancouver and give you a taste of the Rockies.

We did a southbound cruise from Seward to Vancouver, then took a train from Vancouver-Seatle -Chicago-Cleveland. It was an enjoyable ride.