Since she had no firearm, why would she call her grandmother instead of driving to the police station and go in to report the harassment? I'm sure they'd be willing to help in some way.
Her car was found in reverse running, in a ditch, he probably used his car to cut her off
Police stations are pretty sparse in rural areas - she would have done better to never leave the convenience store and call 911 from there or any public area
There but for the grace of God go any of us