Hi Sulis,
Unfortunately I haven't been riding Vietnam, YET. But I did a lot of reseach, just haven't been able to afford the plane ticket. Here are a few links I came across.

http://www.handspan.com/?opt=intro&c...egion/vietnam/
http://www.grasshopperadventures.com/kk.html

I hope you get a chance. Vietnam and Cambodia are on my list.