SCOTTSDALE, Arizona — Sipping a glass of chardonnay on the terrace of Mountain Shadows Resort, I gazed at the unmistakable hump of granite that gave Camelback Mountain its name. At dusk a lilac haze etched the mountain in stark relief against the sky. Looking at it brought to mind a novel that my grandfather, the ultimate student of Old West lore, introduced me to when I was a child. Today, my paperback copy of Zane Grey’s “Riders of the Purple Sage” is dog-eared and well-worn from many reads. Those who know me are aware I am a passionate lover of the American West, which makes Scottsdale, “th…