Depending on how you write the story, the story could infact be, your mind wandering.

Writing a story requires a little more effort and concentration, in my opinion. Especially if you are like me, and hate spelling and grammatical errors, so you read what you have writtin over and over, getting it right (though often missing bits : ( ).

So yes, it is concentrating and requires effort, but at the same time, it can be your mind wandering.