I've done Nanowrimo since... 2005. Won with 50k, won with 100k, won with 100k, won with 111k and a finished novel and well... we'll see how this year goes. No, I haven't had to dedicate all my time to it. In fact, it's not very difficult or time consuming at all... as long as you're a bit competitive, just join a regional group and let them kick you into gear. ^_^ Don't discount writing events... great way to rack up the word count. The easiest week is the first week and the last week... in the first week, WRITE MORE THAN NECESSARY. And I suggest never writing less than 1667 words a day.
I'd say it's all about the pacing, but for me, it's all about the mad crazy days where I write 16k...
It's not that hard. I remember the first year I heard about it. I said "that's impossible! Ridiculous! Why would you want to do THAT?" a few times over and then... well... I did it and it wasn't so bad, so I kept doing it. ^_^
Good luck to you guys... and to you guys going 'maybe next year'... no, no. Try this year. You won't win if you don't TRY. The thing with Nanowrimo is that it makes you stop putting off that zombie ninja romance thriller set in the ashes of a volcanic planet being terraformed by aliens that you've been thinking about for the last three years.
Hey, no one said it had to be a GOOD novel. It's all about churning out those ideas. I assure you, a month is plenty of time to write a first draft of a novel; I did it last year, I wrote THE END 111k words later. Yes... it was a challenge. But a worthy undertaking and not nearly so bad as you'd think when you first see the words FIFTY THOUSAND.
Good luck to anyone trying it!