You could take the train in the morning all the information is here:
When you get to Seward you may want to think about taking a small boat cruise or at least take a trip out to Exit Glacier or visit The Sealife Center before you board your ship. There are also bus companies that will get you to Seward from Anchorage.
Friends are doing the Holland Denali 3 night tour before a cruise which starts in Seward. I don't like the reviews I'm reading about the McKinley Chalet Resort nor do I want to spend 10 hours on a bus from Denali to Seward. So I thought I would try to do my own planning, taking the McKinley Explorer from Anc to Denali,finding better lodging for 2 nights instead of the 3 the Holland package does, then getting to Seward. The problem lies in that to get to Seward I believe I have to take a bus. So I take a train to Anc, then either stay overnight in Anc or try to take abus to Seward so that I can take the 0800 Kenai Fjords tour the next morning in time to embark the ship which leaves at 8pm. If I stay over in Anc I take the 0700 bus to Seward,arriving at 0945 and hope I can catch the 1130 Kenai Fjords tour which I'm guessing is wishful thinking! I also have to consider where we can store out bags while on the Fjords tour. HELP!
The 6:45 am train will get you to Seward in time for the 11:30 boat tour, that is what many people do. I think if you take the train they transfer your bags to your ship but someone with more knowledge can address this. The Fjords Tour will also store luggage while you are on the boat.
I agree with Coalminer, you should rent a car for the Denali portion. A car gives you so much flexibility and more options for lodging.
The coastal classic from Anc to Seward gets in at 11:05, not leaving enough time to make the 11:30 Fjords boat. Any idea how close the train station is to where the boat docks? I could take a bus from Anc and arrive Seward at 0945. Just need a place for my bags. If the Fjords tour will hold them that's nice but I wish I could put them on the cruise ship and then take the Fjords tour!