In my usual way I made the decision last fall to travel by bicycle from Hanoi to Phnom Pehn leaving January 10th, then flying to visit my son in New Zealand on February 15th. I proceeded to book all my flights, then left on a holiday to Mexico. In the meantime I found out that the Vietnamese "Tet" Holiday is right in the middle of the trip from January 26th to February 1st. I was told that the country basically shuts down for that week so all things including public transport and accomodation are usually booked solid. I always start with a general plan, then work out the details later. This method doesn't always work perfectly, but it sometimes adds to the excitement.
I have therefor modified the trip to still start in Hanoi, take the train to Saigon and then start cycling. If it turns out that what I have been told about the "Tet" week is true I plan to hop into Cambodia for that week, return to Vietnam to do the delta area after (which is my main interest in Vietnam) then head up to Phnom Penn. To compensate for the lessor distance I plan on taking a side trip up to Siem Reip in Cambodia and over to Battambang. This is an area I missed on the last trip as we pretty much stayed with the Mekong River all the way from Laos to Phnom Pehn.
The only thing that is reasonably certain at this point is I should be leaving Saigon on or around January 20th. It will unfold.