hi.
we are planning a trip from Hanoi to Hongkong, through Shenzen, and back from HK ofcourse. What are the train/bus routes we can take? Which bus/train companies should we contact that run the above routes?

estimate cost? What we have heard so far is a bus from Hanoi to Lang Son in VN, then Lang Son to Shenzen, with stop at a Chinese considered big town.

Thanks for the help

Viet