Bus Travel in Vietnam
All cities are reachable by bus in Vietnam, but roads can be dodgy, and speeds are often regulated at 70 km per hour.
Most road vets do not recommend traveling at night, because of obstacles (slow motorbikes without lights, animals, etc) and the lack of nearby medical services should your bus be involved in an accident.
Inter-city long distance buses generally leave prior to 6 am, or late at night, and are air-conditioned.
The concept of a central bus station has not taken hold in many cities, so you'll have to tell your hotel where you want to go, and they'll direct you to the right depot, which in many cases will be a tour agency.
Legroom is legendarily short.
Inter-city short distance (local) buses are slow, as they continually pick up and drop off passengers along the way, and do not have air-conditioning.
They don't sell formal tickets, so you'll have to bargain with the driver (figure the first price is double the usual fare).
They also act as merchandise haulers, and one we've seen was actually tricked-out to carry motorbikes, behind a few rows of passenger seats.
Local bus travel can be real hell, as we found out one fine day down in the South ...