We are flying to Ho Chi Minh City in early Feb for two weeks. We have decided we will probably concentrate on the south and the centre of the country as the weather will be a bit dodgy in the north and we don't want to bite off more than we can chew - it's such a big place and not easy or painless to get from A to B by the looks of it. If we love it we will plan to go back and do the north another time.
Main questions: We will be there over Tet, the Vietnamese new year and there is a four day long public holiday. I am not sure what will and won't be open as I keep hearing conflicting reports about this. Any experiences?
I have no idea how long we should be planning on spending in HCMC, especially given the Tet issue - should we just stay for a day or two then fly straight out to a beach resort? I must admit I'm not that fussed about the sound of HCMC - I really wanted to do was go to Hanoi and Halong Bay but it hasn't worked that way this time, although I could still fly up and do Hanoi if it's really worthwhile and there is not enough in the south to sustain our interest. I just don't know!!! 
And which beach resorts are the nicest in the south, or the centre?
We don't want a totally beach based holiday but we do want some laid back down time, and I don't want to run myself ragged zooming all over the place and spending half the time on a plane/train etc. The perfect thing would be laid back, interesting and authentic little towns with lots to do and see, but that benefit from a costal location.
Has anyone done a Mekong Delta boat cruise, either o/night or a day trip?
We will definitely fly up to Da Nang and go to Hoi An and probably Hue, but where else in that centre region is really worth staying? What about Nha Trang? Everywhere seems so spread out, I'm finding it really hard to know where to start!
TIA.