It’s late fall in Calistoga. Weeks of harvest are finally and joyously completed, and the earthy fragrance of ripe grapes lingers in the autumn haze. In a very private corner of the valley, within sight of the majestic Palisades, a family house basks in the slanting sun. And in evening hours, doors are now closed after a summer of open-air activity. The house, in the manner of a traditional Napa Valley farmhouse, was built to transition seamlessly from summer to fall and winter. It’s a house for all seasons, with ample porches, enclosed terraces and shaded decks beckoning the family outdoors, and stone fireplaces for gatherings and contemplation.