I took an overnight train from Hanoi to Da Nang. It was a good experience.
I shared the 4-berth cabin with an Englishman that now lives with his wife in Vietnam, and a Vietnamese couple had the two top bunks. Mine was the bottom bunk on the right (#6), and I actually slept quite well!
It was raining when we woke up the next morning.
My driver picked me up and took me to Hoi An.