The province has a very basic road network, which links Phnom Penh (165km) and Siem Reap (150km) with the National Highway No 6, and the separate National Road 64 to Preah Vihear province with a distance of 126 km. After a rebuild of the former dust road that was long overdue, this is now one of the best roads in the Country. There is lots of bus companies going from Phnom Penh to Siem Reap or back, so while they pass Kampong Thom its easy to drop off there. The companies such as Sorya (near Central Marlket), G.S.T. or Capitol (Str. 182) go usually 7am, 8am, 9am and again midday 12am, 1pm, 2pm to Siem Reap. Prices to Kampong Thom are between US$1.5-2.5.
If you want to shorten the time spend on the trip to Kampong Thom you may take on of the share taxis, mostly leaving near the central market. As they aren?t really the comfortable version of travelling you?ll even have to pay more as with the bus (approx. US$3-6).
Kampong Thom to Siem Reap
It?s a 145 km ride, with the road in nice shape for a while after you leave Kampong Thom town, then it gets a little rougher, but much re-grading work has been done. It's not like it used to be; bomb crater holes used to be so deep that during the rainy season one could have a family picnic at a crater's shoreline.
The Kampong Thom-Tbeng Meanchey (See warning below)
To take the 137 km journey, you follow Highway 6 toward Siem Reap for 5 km to the fork in the road. A sign in English will point to the right side of the fork for TM Chey (Tbeng Meanchey town, Preah Vihear Province) down on Highway No 12. The road here is much improved, as there has been a lot of resurfacing done to accommodate the droves of logging trucks heading to and from Preah Vihear province. The downside of the easier road is the dust that the trucks whip up as they chug along the road. It can be a real hazard as the thick dust clouds practically blind you from seeing possible oncoming traffic when you want to pass these slow moving vehicles.
The final 37 km stretch through the mountains and into Tbeng Meanchey is still tough going. This is how the entire road used to be - bomb craters, erosion galleys, and rocks are all here for your motorcycle fun. It can actually be enjoyable stretch, because the scenery is brilliant. This stretch can also be done during the rainy season, though the road may be slippery and dotted with small mud ponds after heavy rains. Enjoy it.