Coming to Kunming from Hanoi?
Any travel is difficult in China if you dont really have a little bit of the language down so make sure you study. There are a few buses from Hekou. 9:30, 12:30, and some time after 6:00.
You dont want to get stuck in boaring Hekou, so make sure you time it right. Buses going to Hekou from Kunming leave at night, 7:30 arriving early morning.

Two ways to travel.
The bus costs 66 to Kunming. It took a lengthy six hours.
Then theres the sleeper train for 86. A good sleep on a nice train, it arrives in Kunming at 6:00 Am and leaves at 10:20 PM.

From the Nanning bus station Jump on bus #213 this will bring you right down town all the way the train station

Let me tell ya a little secret I learned.
Say your out of time and low on cash but you still want to go somewhere. Heres what you can do. Buy a ticket to somewhere, just a standing ticket on the train. When someone gets out of there seat, take it, then you have a seat, once more people leave you might even be able to lie down on the seat. K you dont want to lie down in the hard seat section of the train, its also possible to buy a sleeper, depending on how well you can negociate, youll do well.

The cheapest way to get from
Vietnam to Kunming is a train - bus transfer.
In Hanoi you can take the hard seat train for 4$ American. You must by this at the train station. It departs at 7:00 AM. You arrive in Lao Cai at about 4:30PM, just enough time to cross the boarder. It is a very quick ride from the train station to the boarder. You should pay only 30 cents. You arrive in China in the small town of Hekou. From there you can take a number of different buses to Kunming. The cheapest one is at 10:50 AM. You arrive in Kunming at about 9:00 PM. Jump on bus # 3 to The hump guest house and let your Chinese adventure begin.

Good luck