The whole reason you're here in Kampong Chhnang is to head down to the river.
If you just want to walk around and take in the sites, as you head down the road from town to the water, you'll see some dirt roads branching out towards the wet lands that definitely worth a stroll just -- it's a picture-book place, full of local villagers going about their business, rickety footbridges, and you'll get 'helloed' about a thousand times by the all the kids.
After a stroll, head to the Tourist Port at the base of the Psar Krom road, next to the Port Police station (there's a big sign that says 'tourist port.') For US$5 per person (no minimum number of passenger) you can get a one-hour tour of the floating villages lining each side of the river -- you'll get a bit of a voyeuristic peek into the culture of the 'river people,' living and doing business in floating houses and on house boats. You'll notice a lot of 'convenience store' boats plying in between the dwellings, laden with goods, stopping off to make sales along the way.
Keep an eye out for the very creative way kids like to get around -- they put an industrial-sized aluminium bowl in the water, hop in, and paddle over to their friend's house. It's a modern take on the traditional circular boats that are used throughout parts of southeast Asia -- in the old days they were made out of natural materials. We're normally not big fans of tours mostly constituted of sitting and gawking, but the sheer size of the floating villages, and the amazingly intricate ways that locals have adapted to life on the water, won us over and we were fascinated. If you've already seen the floating villages of Halong Bay in Vietnam, we think this is much, much better -- especially since they leave tourists alone here, except for the chorus of 'hello! hello!' you'll get, once again, from all the kids.
After the boat tour, your next option is 'the temple tour'. The temples are crumpling and hardly compare to Angkor Wat, but they provide a nice pretext for a leisurely day in the countryside on the other side of the river, an area that is barely accessible via any other route.
You'll be headed to the village of Kompong Haeu about 40 minutes to one hour away by boat to begin your temple tour. There are two options. The cheapest is the local boat. If you show up at the Tourist Port they will try to get you on a private boat -- and they'll try to charge US$15 round trip for a single passenger headed to Kompong Haeu, and US$5 for each additional passenger. Try to bargain and bring this down. The private boats do allow you to see a lot more of the surrounding landscape, but if you've already taken the boat tour, you've seen most of it. So you have some bargaining leverage -- you can always threaten to head to the local passenger boat which only costs 11,000 riel.
To get to the passenger boat, head along the river road passed the Rithisen Hotel. Just past the end of the riverside promenade, you'll see the Provincial Fisheries Office on your left, and on your right, a series of concrete steps down to the water (hard to spot from the street, but they're there.) This leads to the pier the local boats leave from -- be prepared to spend most of the hour-long trip packed in the hold with goods and fellow passengers, though you can always work your way up to the bow to get some air. Boats leave at 06:30, 08:30, 11:00, 13:30, and 16:00, and the fare is 1,000 riel.
Once you get to Kompong Haeu, a motorbike tour of the temples can easily be arranged -- 30,000 riel is the basic price, but paying a little more will get you a more patient driver who will give you more time at the sites. You'll be making a 50km circuit through the countryside and its rural villages, which is the real point of the tour. Along the way you stop at Prasat Thormbdy, which isn't all that much to look at. The next stop is Prasat Phraysry which has much more interesting and intricate stone work and dates from the 7th century AD. There used to be a companion temple here, as in the other locations, but the tree growing to the left of the remaining temple eventually knocked it down. They are now building a modern replacement in back of the tree. Next is Prasat Sor Clor, which is the local name for Prasat Bproh. Finally you'll be taken to Prasat Phunnry, which will require a bit of a stiff, 200-metre walk up to the top of a hill to reach, which gives some nice views of the surrounding country. Definitely not a knock-your-socks-off experience, but a very pleasant day of recreation in the countryside. Your driver will then take you back to the boat.
There is also a local waterfall that you can roll into the trip, but only in the rainy season.
If you plan on taking the local boat back, departures are at 08:30, 11:00, 13:30, 16:30 and the last one is at 17:30, again, 1,000 riel. After that you'll have to pay for a private boat, and since you're stuck, it'll be expensive.