Hawaii is like Alaska in that it offers all the benefits of being on U.S. soil yet has all the exotic atmosphere of a faraway land. It is, quite literally, a faraway land—about 2,500 miles southwest of mainland North America at its closest point. Though there are dozens of islands in the entire archipelago, six main islands host the vast majority of tourism business: Oahu, Maui, the Big Island (Hawaii), Kauai, Lanai, and Molokai.
Unless you want to focus on a single location in the islands, a cruise ship is actually the best way to explore Hawaii. While you can take short hopper flights from island to island while staying at resorts on shore, you will see at least as much and spend quite a bit less if you follow the same itinerary by boat (and you'll only have to unpack once). Even better, you can scout out your favorite places in case you decide to return someday for a land-based holiday.
It's much easier to get around Honolulu, Hawaii, by foot than it is by car. If you arrive a few days before your cruise and want to take in the sights, skip the rental car. You'll find your way to the best tourist spots faster.
Pearl Harbor is the most famous attraction in these islands. The Arizona Memorial Visitors Center commemorates the 1941 attack by Japanese warplanes, and you can visit the U.S.S. Missouri, aboard which the Japanese eventually signed surrender papers and ended World War II.
As interesting as Pearl Harbor is, most people visit Hawaii for its natural beauty. You'll find plenty of it, whether you enjoy fun in the sun, ecological tours of volcanic craters, or views of verdant mountains that tower higher than skyscrapers. Most cruise lines offer a variety of such excursions from island to island, so if you want to see it all before saying your final aloha, that's definitely an option.