I took a train form Hanoi to Hue, which was an overnight trip.
Actually the train was pretty good, with 6 people per cabin & comfy beds too. It was so much better than boating, as it did not lean over, it got you there quickly, it was quieter, & most of all it was dry.
The river at Hue is worth exploring, & so I took a boat up to visit caves, temples scattered round the river banks. I loved the decoration & effort they made for their boats, all with huge Dragon Heads leading the way from the bow.