I'd say wait to book the ticket once there. Plenty of flights and cheaper.

As for good food . . . one placed I loved in Hanoi was Wild Rice. Pricier by Vietnam standards, but a beautiful restaurant and great food.

This was 2 years ago mind you, but looks like it's still a propular place.

http://www.concierge.com/cntraveler/...4/hottables/67

But even just walking around and finding a place to grab pho was always a treat.