The Highlight so far has been a trip to Ha Long Bay and Hour and a half North of Hanoi and if you head this way I would highly recommend you take the two day option which will include cruising the limestone islands on the peninsular, visiting the amazing cave and kayaking on the south china sea with a night spent on board.
The boats are nothing like the ones in the pictures you will be shown when booking but they serve their purpose and as long as you don't concentrate too much on the air pollution a great trip
Expect to pay for what you get I was lucky as I was offered a deal at $130 US which I was going to book but then got hit with a $40 US single supplement (single supplement !!! - I told them I run a website dedicated to never having to pay such a thing) so I ended up with a deal for $85 US and ended up sharing a twin with a 29 year old guy from New Zealand travelling back home and was a mind of useful information regarding his homeland that I have stored away for the near future.