Gilbert Morris 
Gallant Outlaw (House of Winslow Book #15) 

House of Winslow Book 15- Betsy Winslow had always thought that she never measured up to her beautiful older sister, Lanie. So Betsy was deeply flattered when a handsome stranger began showering her with attention-for once she felt beautiful and desirable. Foolishly deciding to elope, Betsy and Vic leave for Indian Territory. Envisioning a life of grandeur as a rancher’s wife, she is sorely disappointed when all her dreams come crashing down. When Lanie hears the news about her sister, she is certain that something is wrong and immediately sets out to help. But Lanie discovers that the only hope of finding Betsy is a shiftless outlaw named Lobo.