Dead Run by P. J. Tracy

Drags and unrealistic but the characters are quite likable. This the third book in this series is the weakest. PW Monkeewrench founders Grace McBride and Annie Belinsky, along with Deputy Sharon Mueller, are driving from Minneapolis to Green Bay, where they believe a new serial killer is just warming up. Unfortunately, their car breaks down deep in the northern woods, far away from civilization and cell towers. A walk through the forest leads them to the crossroads town of Four Corners, where they had hoped to find a landline and a mechanic, but instead find...absolutely nothing.