Set on 4,200 secluded acres of hillocks, ponds, and gardens at the foot of the Tennessee Smoky Mountains, this award-winning resort, a member of the prestigious Relais & Châteaux brand, is awash in genteel luxury, from its splendid spa to its exquisitely appointed rooms, suites, and cottages. But make no mistake, the family-owned property takes the “farm” in its name to heart: Its James Beard Award–winning restaurant, The Barn, as well as the more informal Dogwood restaurant, were early…