Dangerous Heart (Westward Hearts) by Tracey Bateman

Growing up motherless with an outlaw father made Ginger Freeman hard and unforgiving—and for the past seven years she's been driven by a single goal: to make Grant Kelley pay for letting her brother die. Now that she's tracked the hated doctor to a westward-bound wagon train, her mission of vengeance is nearly completed. But the sense of family and community that suddenly surrounds her is unlike anything Ginger has ever experienced. And under the nurturing eye of Miss Sadie, the outlaw's daughter begins to lose her rough edges. Here, in the company of loving, newfound friends, Ginger feels herself becoming part of something much bigger than revenge.

But catastrophe is in the wind when her pa and his gang arrive to infiltrate the wagon train. Will Ginger's new relationship with God tear her away from her family forever . . . and cost her everything she's now begun to hold dear?