So you can drop your bags at the ship, but not board for a while? Are the cruise ships that explore the Kenai Peninsula lacoted right there at the same dock? What about the kayaks?
Yep just drop off your bags- no the tour boats leave from the docks off the Seward Highway probably a 1/2 mile+ from the ship dock. Depends on the Kayak company??? but not usually? There is a map online from the Seward visitor site www.sewardak.org
that will be helpful to you- be certain to request the guide. If you are planning arriving via the train and then the 11:30am Kenai Fjords boat trip- it would be best to take your bags right to Kenai Fjords- they will store them for you- you may not have time to cab to the ship from the depot and return for the boat tour.