A couple lines offer one way Vancouver to (basically) Anchorage v. Vancouver round trip. Both options are 7 day.
The one way voyages visit College Fjord or Hubbard and cross to ~Anchorage, while the round trip voyages head back down the Inside Passage to Vancouver.
I would not be staying on in Anchorage.
Expert Cruisemates, what advice would you give on deciding between these options? I suspect the one way trip would be more expensive in the end, since it would involve two one-way airfares, one of which is from Anchorage. But this is just a guess.
What say you? (My questions have gotten so many great answers - thanks!)
Unless I was going to do a land tour up to Denali I would choose the round trip option. I must say however that I haven't seen College Fjord yet and I hear it's wonderful. Some like it more than glacier bay. But much more convenient logistics wise doing the round trip. We prefer leaving from Vancouver but have done Seattle which was fine too.
As you suspect, the one way trips are generally a bit more expensive in the long run due to the open-jaw airfare. A good TA can find an open-jaw at considerably less than two one way fares, but still probably more than a round trip.
College Fjord does get some good reviews. It did not impress me, in no way comparable to Glacier Bay.
Crossing the Gulf of Alaska to Anchorage was one of the few times we encountered really rough water in Alaska.
It is not necessary to go on to Anchorage in order to see Denali. There are many variations on cruise tours which will take you there.
Alaska cruises have so many choices available, and you are asking very basic questions, so the very best advice I can give you is find a good local Travel Agent who is a CLIA Accredited Cruise Counselor (look for the agent's diploma on the wall, not just an agency sticker). Ask your friends and co-workers for a recommendation. The service is entirely free to you. ACC's are trained to find the very best cruise for you, after learning your personal situation and preferences, and work hard to get you the very best rate.
You can check out reports and pictures from our 8 trips to Alaska, including most of the options, in the link in my signature below.