Just completed the journey today (Sept. 2014)
- bus from Kunming to Hekou left at 1:30 PM, 149 yuan, no thieves, 2 police checks (only foreigners)
- arrived in Hekou at 8 pm
- took taxi to border, 10 yuan (5km, totally worth it)
- crossed border at 8:30 pm (chinese time)
- money exchangers offered better rate than official rate !
- took taxi to lao cay train station, 40k dong (5km, absolutely fine)
- took train to hanoi leaving at 8:20pm vietnam time
Tickets were 280k for soft seat and 640k for hard bed. Someone offered us 2 beds for 400k each, took the offer and everything was fine
- arrived in Hanoi at 6am