Most people start by picking a cruise line. Start with the route instead, it decides your flights, your glaciers, and whether a land trip fits.
from Seattle or Vancouver
Round-trip Inside Passage
Fly in and out of the same city. You get the classic ports (Juneau, Ketchikan, Skagway, sometimes Sitka) plus a scenic glacier day. Seattle round trips also stop in Victoria, British Columbia. The easiest Alaska cruise to plan.
Vancouver to Seward or Whittier
One-way Gulf of Alaska
Sails between Vancouver and the ports near Anchorage, in either direction. More ground covered, often a second glacier day, and it sets up a land trip. The trade-off is open-jaw flights, which usually cost more.
cruise plus Denali by land
Cruisetour
A one-way cruise paired with a few nights inland, usually around Denali National Park. Princess and Holland America run the deepest land programs, with their own lodges. The best way to see Alaska if you are only going once.