Rattana keeps up the patter as he jogs behind my ox cart under Cambodia's blazing sun. What's my name? Where am I from? How old am I? He's 11, with a wide smile, natural charm and excellent aerobic capacity. His friend, who's running too, folds the petals of a pink lotus into intricate shapes, periodically offering it for sale.

The ox cart ride is one of the most charming shore excursions available to passengers aboard the Cruiseco Adventurer, the newest of an estimated 16 riverboats plying the waterways between Vietnam and Cambodia. My fellow 47 passengers and I are paired off and poured into carts normally used for hauling rice, firewood and vegetables. Today they're hauling a bunch of Australians from all walks of life - there's a policeman, an artist, GP, retired tradies and IT specialists - along a bumpy elevated track above flooded rice paddies somewhere north of Phnom Penh.

Village children assign themselves a cart, chatting, singing and giving lessons in basic Cambodian - coconut is "doung", papaya is "lahong", banana is "chek" - while running along at full speed. The clanking of cowbells and thwack of rubber thongs is a soundtrack to the ride. And as we file back onto our riverboat - to leave our mud-encrusted shoes for staff to clean, to wipe away humidity with cold towels, to slurp glasses of iced tea - the children gather into a choir to sing If You're Happy and You Know It. They clap their hands with gusto as we cross the gangplank - a few steps that seem to signify the chasm between us and them. It's heartbreaking enough that one passenger returns to hand out dollar bills, inadvertently breaking up the performance.

Moments such as this pepper the Adventurer's 550-kilometre route between the Mekong Delta in southern Vietnam and Siem Reap in Cambodia. Cruiseco used to charter the Indochina Pandaw - one of the atmospheric teak-clad riverboats that have deep verandahs and channel the colonial era of cruising. Taking lessons from that boat, Cruiseco's custom-built 68-metre Adventurer with capacity for 60 passengers, ditches the communal verandahs and their wicker chairs in favour of larger cabins, each with a small private balcony.

The seven-night cruise itinerary has also been tweaked after feedback from passengers, who said they wanted fewer shore excursions and more night-time entertainment.

The route can be sailed in either direction but I'm on the inaugural sailing heading north-west from the Mekong Delta towards Cambodia. For the first three days, we traverse the mighty Mekong. Once we reach Phnom Penh at the confluence of three river systems, the Adventurer is steered up the Tonle Sap River into Tonle Sap Lake - a body of water so large it dominates the map of Cambodia. Siem Reap is just off the lake's northern shore.

Unusually, the Tonle Sap flows in two directions. From June to October, when monsoonal flows turn the Mekong into an impenetrable torrent, the Tonle Sap backs up, reversing towards the lake. This river is less busy, more intimate than the Mekong, which is plied by all manner of cargo ships. Both waterways feature floating tangles of invasive water hyacinth.

The pace of change along the rivers, especially in smaller communities, provides a challenge for cruise companies. At a riverside silk-weaving village in Cambodia, the intensity of the salesmanship is so strong most passengers wish they'd been warned about it. Just a few cruises later, the chief executive of Cruiseco, Steve Lloyd, says that visit has already been moved to another village. "Three years ago, these people were shy and reticent - hospitable but completely untouched by money," he says. "Now some of the villages that are visited by the big boats actually bring stuff back from commercial factories to sell in the village. In five or 10 years, local cottage industry on the river may have reduced to a stage where it is only done for the tourists in small sectors of the community."

For Lloyd the highlight of the cruise, which showcases floating villages and towns where people simply go about their business, selling baguettes, fish or fruit from makeshift stands, is that people don't need much to "find happiness, humour, generosity, loyalty, community". "It's a great reminder for us to review our values," he says. "I'm not sure I would have understood this as well in my 20s but probably needed the lesson even more then. On each occasion I have done this trip, I have returned humbler."

This is my first river cruise and, just like ocean-faring cruises, food takes on the utmost importance. Lunch and dinner are elaborate three-course affairs, with choices between Asian and Western dishes such as Vietnamese-style crispy marinated river prawns with sticky rice or roast lamb with ratatouille and bacon-wrapped potatoes. Local beers and spirits are included; wines from a global list cost extra.

Between meals, shore excursions shape our days. In Sa Dec, Vietnam, we take tea inside The Lovers' Museum - the former home of Huynh Thuy Le, the older, Chinese lover of French teenager Marguerite Duras. She immortalised their affair in her 1984 book The Lover. In 1992 the book was adapted to film. Passengers are given a DVD of the R-rated movie to watch in their cabins. No one seems to mind the raunchiness - in fact, older women passengers remark on actor Tony Leung Ka Fai's pert bottom.

Before we reach Phnom Penh, the airconditioned lounge (where there's free and surprisingly reliable wi-fi) is turned into a communal cinema for a screening of The Killing Fields. As it turns out, our day in the Cambodian capital starts with death: the Royal Palace is closed after the October passing of King Norodom Sihanouk; it will reopen after his February 4 cremation. The Silver Pagoda in the palace complex still makes the visit worthwhile: tiles of pure silver click-clack under our socks and bare feet as we pad towards a golden Buddha studded with 2086 diamonds.

For lunch we head to Raffles Hotel Le Royal, where linen-covered tables and a buffet await underneath the canopy of a sprawling tree in the courtyard. After lunch, most - but not all - head to the country's infamous "killing fields" 18 kilometres outside the city. Our Cambodian guides tell stories about family members who were among the millions who died between 1975 and 1979 under Pol Pot's despotic regime.

These atrocities are brought home even harder at the city's grim S21 detention centre - also known as the Tuol Sleng Genocide Museum - where people were interrogated and tortured before being killed. Among the rows and rows of photographed faces, three are seared in my memory: one man smiles as though he's never been happier, another looks beyond terrified, and then there's the Caucasian features of West Australian David Scott, taken from a yacht off the Cambodian coast in 1978 to become another Pol Pot statistic.

When S21 was discovered, just seven people were alive inside. One of the two still living today is in the grounds selling a book about his life, simply titled Survivor. Chum Mey is 82; via our guide we ask how he feels to be standing in this place where so many of his countrymen died awful deaths. "It makes him heartbroken - he cries every time he thinks of it," comes the reply. "But he's happy you're here to learn about the story."

FAST FACTS

Getting there Singapore Airlines has a fare to Ho Chi Minh City for about $1100 low-season return from Melbourne and Sydney including tax. Fly to Singapore, then to Ho Chi Minh City. See singaporeair.com.

The Cruiseco Adventurer's 11-night itineraries start from either Ho Chi Minh City or Siem Reap. Fares, which start from $3999 a person, twin share, include Singapore Airlines flights from Australia, two nights' accommodation in both the Caravelle Hotel in Ho Chi Minh City and Raffles Grand Hotel d'Angkor in Siem Reap, city tours and shore excursions, all meals on board the boat and local beers and spirits.

Australians require a visa for a stay of up to 30 days in Vietnam. A visa is also required for entry to Cambodia. A Cambodian visa can be obtained on board; a visa for Vietnam should be obtained before undertaking travel.

When to go Cruises run until March 24, and resume on June 9 through to February 9, 2014.

What to pack A good insect repellent, wide-brimmed hat, US power adaptors.

More information cruising.com.au, phone 9492 8520.

ON BOARD THE SHIP

Between shore excursions — to temples and monasteries, rice-paper and fabric factories and floating fish farms — passengers can easily while away the hours on board.

The airconditioned Saigon Lounge includes a library with board games, guidebooks and coffee-table books on attractions such as Angkor Wat; there's also a computer nook and free wi-fi. The lounge also hosts film screenings, cooking classes, dance and music performances and talks.

The outdoor Sun Deck houses a whirlpool — a great place from which to take in a sunset — and plenty of loungers where old and new friends natter away for hours. Early risers can find coffee and tea here from 6am.

Spa treatments such as massages and manicures are popular; book them early, along with DVDs from the ship's library (recent releases are in high demand). Those interested in working off all those multi-course meals and drinks will find a treadmill and exercise bike outside the spa treatment rooms.

Katrina Lobley travelled as a guest of Cruiseco.