Surrendered Hearts (Heartsong Presents)

is book #595 of the Heartsong Presents line.
==Book Description==
Isabel Fairchild wants her independence. She's tired of her parents' strict rules and of the constant comparisons to her more conventional older sisters. And she certainly doesn't want to marry a man twice her age! Boarding a train to the Arizona Territory, Isabel's great adventure in freedom is threatened when another passenger steals her bag. 
Slade Stanfield sympathizes with the beautiful young woman and offers her a job as a companion to his crippled sister. Isabel accepts but wonders if she made a mistake. Slade's desire to control everyone on his ranch infuriates Isabel, while her zest for life and adventure terrifies him.
Still, there's a mysterious attraction growing between them. Will they try to deny their feelings, or will hearts surrendered find peace and joy for a lifetime?
(Description from paperbackswap.com)