In Cambodia the road system is evolving very fast, usually for better roads, but sometimes not! That is often the case during or after the rainy season, or simply because no road maintenance has been carried out recently.
In any case, before leaving, you should ALWAYS ASK LOCALS about the route you plan to take...
Apart from that:
-we drive VERY SLOW to enjoy the countryside and to avoid accidents, which we don't want to have in the remote: don't expect any
emergency services there!
-we try to make the driving in the MORNING: first, we hate to be caught in the night with a technical problem, second, we like enjoying the afternoon at the place we're heading to,
-we always bring WATER because we get thirsty and humans need to drink a lot in the heat,
-we like to have a SPARE INNER TUBE with us (basic tools are good too),
-we take a FIRST AID BOX, though we haven't used it so far...
-we DON'T GO ONE person: even though in the Cambodian remote you rarely see nobody, sometimes you're really on your own,
-our phones batteries are charged in case we need to call MUMMY, thought beware that in some areas (now few) you might not have any network coverage.