Winning the Cowboy's Heart by Karen Rock

Jewel Cade wants two things - one of them is Heath Loveland.

Rocky Mountain cowgirl Jewel Cade has her heart set on becoming range boss of the Cade ranch. But first she has to accompany the son of her family's long-time enemy - and her off-limits secret crush - on a cattle drive across Colorado. Discovering Heath shares her attraction only makes for a rockier road. Because Jewel has a sneaking suspicion that if she drops her guard, the cowboy might ride off with her heart.