Young Adult novel - Teen girl hikes the Appalachian Trail

I read this in second grade (I believe it was in my second grade teachers classroom) so publish date had to be before 2009 at least.

Key things I remember, her parents were divorced and lived in separate states. Mom lived in near the south end of the trail and her father lived in Kentucky. There was a scene/chapter where she was in the car with either her mother or father and they got into an argument so she just jumped out the car and rolled down the hill they were driving beside.

Cover was a girl in shorts and hiking boots stepping up a rocky ledge with mountains as the backdrop.

Thats all I can remember and I cant find it anywhere, thank you for helping if you know it.