Roughly two-thirds of the three million people who visit Alaska each year arrive by cruise ship, and a significant slice of those extend the trip with a land tour. That combination — a seven-night coastal sailing plus three to ten nights overland — is what the industry calls a cruisetour, and in Alaska it's more popular than almost anywhere else on earth.

The reason is geography. Glacier Bay National Park can't be reached by car, and neither can Juneau. Meanwhile, Denali National Park and Ketchikan are more than 1,100 miles apart by road — a 40-hour drive. A cruisetour stitches the two worlds together using ships, rail cars and motorcoaches, so you can hit Juneau, Skagway, Ketchikan and Glacier Bay on the water, then push inland to Denali, Anchorage or Fairbanks without touching a rental car.

Six cruise lines run most Alaska cruisetours: Princess, Holland America, Royal Caribbean, Celebrity, Norwegian and American Cruise Lines. Princess leads with 28 itineraries from $1,479 per person; Holland America offers 19 from $2,489; Celebrity, Royal Caribbean and Norwegian sit in between, with American Cruise Lines' small-ship option from $6,335. The two Carnival-owned brands, Princess and Holland America, dominate because they own their own infrastructure — Princess has five wilderness lodges (two at Denali), glass-domed rail cars and its own motorcoach fleet, while Holland America owns a Denali lodge plus hotels in Alaska and Canada's Yukon. Some Holland America tours even cross into Whitehorse.

The other lines contract local hotels and transport instead, which can mean a perfectly good trip but less of that seamless lodge-to-train experience. Note that land-portions meals and most excursions usually cost extra, though some higher-end tours include them.

Nearly all cruisetours start in Anchorage, Fairbanks or Vancouver (Norwegian occasionally runs Seattle departures). Start in Alaska and you tour first, cruise second; start in Vancouver and it's the reverse. Either way, the cruise segment is typically a one-way, seven-night Gulf of Alaska sailing.

If you've never been to Alaska and want the broadest sweep of the state — tidewater glaciers, whale-watching, gold-rush towns and Denali wildlife — a cruisetour is the least stressful way to do it in one go, even for travellers who normally avoid group trips. First-timers should compare itineraries carefully, though: the destinations, length (10 to 17 nights total) and level of comfort vary a lot between operators.