Vietnam visa for travelling by train from China
my wife and i plan to travel by train from China to Viet Nam in april 2012, go to Hanoi, spend a few days, then go by train to HCM City, then by bus to Phnom Penh. can we purchase visas at the Chinese border, or do we have to purchase them on line before? Since we arent sure of the exact day we will enter Viet Nam, is it ok to put in expected dates of arrival and departure? Thank you.