My wife and I will leave Guilin on 28 March and travel to Nanning in order to pick up a visa to travel to Vietnam. Any suggestions as to the best way of  travel to, firstly, Nanning, e.g. bus, coach or train, and then on to Hanoi (Vietnam), will be much appreciated. We then plan to take the train from Hanoi to Ho Chi Minh City, probably returning from HCM to Nanning by air. Again, any travel tips would be very welcome. Thanks.