apply chinese visa in Hanoi

Hello,
In april we will go to Vietnam to stay there for a month. We would like to apply for our chinese visa in Hanoi (we our from the Netherlands ourselves). A have a few questions about it. First of all, the offical website of the Chinese ambassy sais that we need the following: Documents showing the itinerary including air ticket booking record (round trip) and proof of a hotel reservation.

-Does this mean they want airtickets showing that we go from Vietnam to China and return to Vietnam again (round trip?). Our is it also possible to fly from China to another country?
-And is it also possible to book train or bus tickets to go in and out of China instead of air tickets?

Hope you van help us,
Thanks in advance,
Pia