Can luxury and real adventure go together on a cruise? Tom Huth boards the good ship Orion, bound for remote Pacific islands. Plus: We pick more cruises, from the Amazon to Alaska, that promise days of spectacle and nights of pampered bliss 

As the cruise ship leaves Cairns, in northeastern Australia, and heads out over the Coral Sea bound for adventure in New Guinea and the Solomon Islands, the captain's voice booms through the overhead speakers: A tropical cyclone is moving west-southwest from the Solomons, and we might feel some unusually large swells. "It will be interesting," he muses, "to see what happens."

That night, we fall asleep to the sound of the waves surging against the hull and retreating back to the deep. Then, after a day spent at sea (and after the cyclone has torn up the coast we've left behind), the new dawn finds us slipping silently through a mirrored bay amid the green mountain fastnesses of Papua New Guinea.

Smoke from campfires hangs low over the jungle. Shacks on stilts appear at water's edge, children waving our way. A mahogany-chested fisherman glides past in a dugout canoe. From Deck 5 I try out my pidgin, asking his name: "Wanem nem bilong yu?" Then we see the grass-skirted dancers waiting in the shade.

Is it possible to access real adventure from a cruise ship? That is the plan. Can a passenger have genuine cross-cultural encounters during his limited time ashore? That's the challenge, and I'm sleepless with anticipation. The vessel for these schemes is a small luxury-expedition ship: the MV Orion, the length of a football field, with only forty-six guests for this maiden itinerary. She has a shallow draft (twelve and a half feet) for getting where most cruise ships can't, plus ten motorized rafts to beach us through the surf like the Marines at Guadalcanal.

Papua New Guinea and the Solomons look to be ideal candidates for small-ship exploration: They have two of the world's most intriguingly primitive societies, unfortunately with tourism infrastructures to match. If you fly in, you have to lay over in a capital known for street crime (Port Moresby) or the afterglow of ethnic cleansing (Honiara)—then pray that your internal flights aren't canceled. If you drive, the few bad roads don't go far, and if you're involved in an accident, you're advised to keep driving to escape potential roadside justice.

We cruisers instead merely trip down the gangway, our tummies full from breakfast, and we're in the port town of Alotau, at the eastern tip of New Guinea's mainland. We have seven and a half hours to nose around, by guided tour or on our own. Locals wearing secondhand Western clothes pad along the shoulders of the one paved road, barefoot or in flip-flops, their mouths stained safety-vest orange from chewing betel nuts, and I fall in with them, exchanging good mornings. One man presumes, "You come from big ship?" A billboard warns: "Lukautim Yu Yet Long AIDS" ("Beware of AIDS"). A young guy gives me a low five. I ask another man, "What is there to see here?" and he intones, "The slow development of the town." He thinks. "Maybe you could invest." I parry, "That would help you." He smiles. "And help you too."