In Shining Whatever (Three Magic Words Trilogy #2)
Carolyn Brown

A professional bull rider turned rancher, Hart only has eyes for Kate, but she is one sassy piece of baggage -- even more so than back when she was a teenager and she'd first caught his eye.
Trust is hard to regain once it's been broken, and neither of them are willing to take chances with matters of the heart -- not anymore. And then Kate's Cajun grandmother, Maw Maw, and some of her other relatives set a plan into motion to abandon the two on a primitive island in the bayou. No cell phones. No electricity. No running water. And no one to talk to except each other.
Will they figure out what Maw Maw already knows: that fate is drawing them together and they need to learn to trust their hearts?