I would recommend heading into Hanoi. The Water Puppet Theater is wonderful! Take a look at this link:
http://www.globosapiens.net/travel-i...Hanoi-958.html
A stroll along Hoam Kiem lake is a nice way to relax, before or after the show. Dinner at Hoa Sua Training Restaurant. French cusine, prepared and served by street kids being trained in the restaurant business. The chocolate mousse is the best I have ever had. They also operate a bakery, but I haven't been there.
If you are transitting through Viet Nam/Hanoi, you made need a visa to leave the airport - does anyone know?
Kate