SAN FRANCISCO — Todd Helton now regularly drives his two daughters to school or other activities back home in Tennessee, a huge life change for Colorado’s former All-Star first baseman. He had no idea walking away from baseball would be such a daunting and overwhelming adjustment. The daily routine that had become part of his DNA — the bantering, the batting practice, the games — replaced by chauffeuring kids, helping around the house and some golf. “It was the hardest thing I’ve ever done in my life,” Helton said.