For the southern part of the Cardamoms, we asked the locals for advice (even if very few can speak English): indeed, some roads are not passable depending on the season or the works. If a Cambodian tells you to turn around, listen to him! Even if you have to take a longer route, it will save you from getting stuck. There are mostly red tracks. If you pass near the hydrolic dams, the roads will be better maintained. Watch out for wildlife (boars)! These are roads with a lot of gravel, probably among the most difficult in Cambodia. We were very happy to see beaches and sea. We spent several days at the Wild Young and Free (English and French speaking) run by a couple of bikers.