Nothing in the north worth seeing? What?
Hanoi is a good experience, I liked it, however I could see how it's not for everyone. I liked it because it was cool to see the dichotomy vs. the westernized south of the country. More importantly, world heritage sight Ha Long Bay is ####ing amazing, and you can hop on a luxury boat and stay overnight in the bay, plus cruise through the National heritage site caves that rim the coast and are truly spectacular. Ha Long Bay was one of the most beautiful places I've ever seen...
http://www.google.ca/search?hl=en&q=...KaqmiQKN4YDwBA
Also in north Vietnam is the town Sapa, which is about 20 km from the China / Vietnam border, and is a pretty cool little town to cruise around and check out life in the north, plus the rice patty fields. You can access by train from Hanoi.
Secondly, if you're headed to Laos, first of all excellent call. The place is also incredible. If you're going to be in Vientienne, you'll be close enough to the Gibbon Experience, which was created to help preserve the jungle in northern Laos, and is along the Thai / Laos border. It's a little expensive but 100% worth it... guaranteed.
http://www.gibbonexperience.org/
You live in tree houses for 2-3 days and fly around the tops of the jungle in massive zip lines, some of the biggest in the world. Access is sometime tricky and you'll need to hike in, but if you're the adventurous type I recommend this 100%, and you'll likely meet some great people too in the hut. You can also access this from Chang Mai in the north of Thailand, they'll take you there if you want to line that up.