I think the longest I'd ever written before this was a story that got to around 17k. o.o By then, I spent so long getting hung up on the details that I gave up on the story. >__o
So NaNo is really good for people like me, who get discouraged and hung up on details. xD Forces you to just push the story onto the page, because then you finally HAVE something you can edit.
But it's not actually as horrifically difficult as it sounds, as long as you keep up! That's the real trick. You only have to write 1667 words a day to make it. (Which, well, if I count the total of all my RP posts, I wrote that much a day anyway, easily, between them all!) The trick is to not fall behind. There were times when I missed a day, and oh man, that's when it got hard, because suddenly instead of writing 1667, you have to write double that to catch up, and if you don't make it up, it'll spiral fast. xD
The other challenge is in resisting the urge to fix things. xD Including plot holes. I mean, like, there were times where I actually wound up leaving a character behind/forgetting a character but it was like, "Welp. Oops. |: Oh well." I also got ideas that'll change the entire course of the story. xD But I can fix it and stick that stuff into the next draft. You just have to shut up your internal editor and keep pushing forward.
It's tooootally doable! <3 And its a lot of fun! xD There were points where I got stuck and was like "I DUN WANNA WRITE NO MORE WAAAAH" (especially toward the final stretch, especially those last 500 words; that was painful. xD) but just gotta push past it and keep chugging!