Vietnam forum

Hi guys. As part of a larger 2 month Southeast Asia tour in September/August, a friend and I will be spending time in Northern Vietnam, Laos, and possibly Cambodia. The general preference in terms of travel style is: keep the overly touristed places to a minimum, without missing out on must-sees (eg Halong), generally trying to get a feel for the place/locals/way of life (eg just sitting around in cafes and walking around, instead of rushing from museum to mausoleum), without being drowned in package tourists and locals trying to sell us trinkets the entire time, and being flexible enough to change plans to some degree when we feel like it. Especially keen on pristine natural landscapes.

Our plan for Northen Vietnam (possibly dipping down into Central) is generally: about 5 days hanging out in Hanoi (pho!), 3 day Halong Bay tour (with Handspan), and depending on how long we stay, visiting places like Mai Chau, Ninh Binh & surrounds, possibly Northern mountains, and basically anywhere where we can get a good feel for the landscape and the people (am considering Hoi An/Hue as well, but the overly touristed nature of the place is making me hesitant).

Here is my quandary: We have the option of either staying in Northern Vietnam for 3 weeks, or staying only 2 weeks and spending the 3rd week in Cambodia (where we have distant family friends). A week in Cambodia sounds great (about 3 days for Angkor and another 3 doing daytrips from PP I think - not sure at this point), but I am wondering if reducing Northern Vietnam to 2 weeks will make us feel rushed, miss out on some stuff we should've checked out, and generally change the easy-going nature we'd prefer. Or is 2 weeks plenty for the region? Because we'll be visiting Laos as well, particularly the North, I'm guessing that it might not be a massive loss to miss out on the Northern moutainous areas of Vietnam (either Sapa or the Northeastern mountains) as we should be able to get plenty of jungly mountain trekking and hill-tribes in Laos - is this a reasonable assumption? Also, there is a decent chance that we'll be able to visit Cambodia another time (say for a more relaxed 2 weeks) if we miss it this time.

So, that 3rd week in Vietnam, or 1 week in Cambodai?

Cheers fellas.
Ps. Any suggestions for interesting places not mentioned to check in Northern Vietnam would be appreciated! Any other feedback on the places mentioned would be great as well.