I did this trip last christmas, really great tour, take a lightweight waterproof coat, we had a couple of days with heavy rain, other than that shorts and tee shirts, i took a mixture of currencies and was fine, all the add ons were worthwhile doing. Malaysian airlines A380, plenty of room and good inflight service. I managed a ride on the back of a moped in Ho Chi Minh city, it was a great experience, that said it is not something the local guide and tour manager encourage because of the risks (very basic crash helmets), so wouldn't recommend unless you have been on the back of a bike before, even then make sure the tour manager knows that you are doing it. The Rex bar is a great place if you have a free evening in Ho Chi Minh city, you can relax with a drink and food and watch the chaos on the roads from above. In Hue, the DMZ bar is worth a visit, good value for money and great atmosphere.
