Hi Simon,
we are just back from a four-week cycle trip through Vietnam (15 November - 15 December 2003) and you may be interested in our four internet reports under
www.tandtontour.com.We got the overnight train from Hanoi to Hue, and cycled the coast from Hue to Nha Trang going south (about 700 km). We also made side-trips to Halong Bay and Mekong Delta. It is no problem to leave your bikes in the hotel in Hanoi or Saigon to do these trips if you don't have time to cycle there. We actually hired a motor bike to drive from Saigon to Cantho, a 360 km round trip, to see the Mekong Delta as we didn't have enough time to cycle this stretch and the countryside is far from scenic heading out of Saigon towards the Mekong Delta.
Don't think you would have any probems with the bob. The trains and buses transport anything and everything, and they are very expert at securing things to the roof (bus). Our brand-new bikes survived plane, train and bus transports.
Are you using Lonely Planet "Cycling Vietnam, Laos & Cambodia" to plan your route? If you don't have a guide book, you must be aware that you sometimes have to cycle very long stretches along the coast (120 - 130 km) to find accommodation. Loney Planet lets you plan your day ahead without having any major panics about not finding anywhere to sleep.
Cheers,
T&T on tour
www.tandtontour.com