No Country for Girls by Emma Styles

When Charlie accidentally kills her sister's boyfriend Daryl, she has to go on the run to avoid capture. Charlie had taken a gold bar from Daryl's stolen stash, but now finds herself in possession of many more. Joining Charlie on her journey on the Great Northern Highway is a young woman named Nao, whose reason for coming to Charlie's house also involved the gold. Taking place over a week, No Country for Girls is a suspenseful ride through remote Australia as Charlie and Nao fight for their lives.