The word narrator always makes me think of the closing scene from "Walton's Mountain", an OLD family friendly prime time TV show from back in the day of three letter networks. MTV wasn't even around yet. Archie Bunker may have been though.
Anyway, it's dark and the camera is outside John-boy's window looking in on him as he sits at his desk writing in his journal. Slowly the camera pans out. the view is wider and the voice (Earl Hamner I think) is talking, in the character of John-boy I think. Maybe the voice is simply reading what John-boy is writing. I don't remember. As an aside I do remember John-boy had a really hot sister. Mary Ellen if memory serves. She might have been my first crush. I wonder where she is now?
Anyway, I am using the narrator's voice to describe setting, feelings, and thoughts. Things that have no way of coming out in dialogue. Time will tell how it turns out.