Never Far Away by Michael Koryta

 Ten years ago, Nina made the hardest choice of her life: She faked her death and disappeared to keep her family safe from the wrath of her rich and ruthless employer--who realized she knew too much. She made a new life in the backwoods of Maine and felt safe--until she found out that her husband had died, leaving her two kids "orphans."

But retrieving them alerts the man who wants her dead. And so begins a deadly game of cat and mouse in the wilds of Maine. This is really quite the page-turner, with a feisty woman as the action hero.