I feel it's still going well, though the plot has taken a couple of unexpected turns, improving the story, I think. And a couple of characters have sneaked in rather earlier than I initially expected. But that's the beauty of working on a loose framework largely dictated by the way characters interact. It's more fun when you're not certain where the next chapter will take you.
I'm part way into chapter 6 now, and looking forward to another journey tomorrow. This NaNoWriMo challenge is proving more fun, and harder work, than I expected and I'm glad I decided to have a go this year.