I just returned from Vietnam about 6 weeks ago. Flew to HKG, then Thai to BKK on a zonal ticket. If you're eligible for the zonals, they're great! Buy one ticket on a carrier and use it on any ZED carrier for the same or lesser zone. We purchased the ticket intending to travel on CX, but slept too late and had to take a later flight.

We spent some time in Thailand before going to VN. Be aware that, depending on where you're from, you may need a visa to get into VN. We got ours at the VN Embassy in BKK. Both AF and TG fly between BKK/(...forgot the id for Hanoi!) and BKK/SGN. If you plan to visit only Hanoi and Saigon, it might be cheaper to fly from one to the other via BKK! We flew from Hanoi to Hue, then Saigon. If you fly on Vietnam Airlines...well, let's just say it'll be interesting!

We found they accept 3 types of currency in the country (VN), credit cards (most larger places), local currency, and US Dollars. You might want to take a few hundred US dollars in small ($1?)denominations.

VN is a very worthwhile trip! Everyone was very friendly and most spoke english--at least in the cities.

Let me know if you want more information and I'll send you a phone number.

Gary