Plotting is a skill that I envy. I don't often know where my story is heading until it comes out on paper. However, I found that Donna MacMeans' W-Plot makes sense. Here is a link to an article that I wrote after last year's Y-City Writers Conference on the W-Plot. It gives you an idea of where you should be in your story by percentages. You should arrive at your inciting incident 10% of the way into your story.
For NaNo, I know a young lady who writes what she wants to see happen for everyday of November.
If you can plot, do so. Remember that it's okay for your characters to take off on tangents. You might actually like where they take you. A Plotter and Pantser combination is a that can create fabulous stories.
I am a pantser. I begin with a basic idea. I create my main character and then I start writing with that little germ of an idea... Other characters come in as the story needs. The plot unfolds as I write. For instance, in John Dunham's Diary, John developed in a previous short story. I fell in love with him and wanted to know more about his life and what brought him into Miri's story, so I sat down at his beginning and wrote a story about him. Or rather he told me his story and I typed it up. John still talks to me, so his story isn't finished yet.
But in preparation for NaNo, I let the seed germinate and begin to think about my character. To learn more about him or her. Also, this is a good time to research the era or background of your character. The setting, any technology you might use, etc.
I suggest trying to plot your story. At least so that you have a guideline to use to keep you on track for reaching your 50,000 word goal.