Burma is still fairly retricted for off the cuff travel.
Laos is a friendly place for a few days.I do some Visa runs to Vientaine.There are some threads on there already.
Cambodia has been visited by many BMs and they have done reports on it too.Phnomm Penn is good for a look see and the southern resort of Sirinookville was featured on recent travel programmes.
The train journey from Siagon to Hanoi is also supposed to be good to do.