We also did only the river cruise as part of a broader package that APT travel provides. The trip was advertised as requiring a "good level of fitness" to participate in the excursions. "Good level of fitness" included passengers who required a good level of assistance simply to get on and off the boat. We were expecting an active holiday. It was definitely more sedentary than what we expected from the advertising.
The trip was advertised as an "8 day river cruise". In small print it did say that the itinerary would be subject to change dependent on conditions and weather. The truth of the matter is that the conditions for cruising all the way up the Mekong and Tonle Sap waterways from Saigon to Siem Reap are right for a short two months of the year, during the rainy season. For the rest of the year the water levels are too low, to allow for the passage of the ship. Instead we had to endure a 6 1/2 hour bus ride from Phnom Phen to Siem Riep, with two rest stops where APT generously covered the cost for the use of the toilets. On arrival to Siem Reap, those of us who were not part of the ongoing land tour, were basically ignored and left to our own devices. Not even refreshments were provided.
On the plus side, the ship, the AmaLotus, was beautifully appointed, with highly capable and professional staff. The food was outstanding, though the wines served with the meals were pretty mediocre. The saving feature on the cruise were the guides. We were provided with local guides both in Vietnam and then in Cambodia. They shared freely of their abundant knowledge about their countries, both from an historical perspective, as well as the a forward-looking cultural perspective.