Willie Nelson takes a hit of the cigarette-sized vaporizer in his gnarled hand, exhaling a small cloud, before placing it on the foldout table in front of us. We’re seated in the cool enclave of his tour bus, at the entrance to his sprawling property just outside Austin, Texas, which he has dubbed the town of Luck. Up a hill and around a corner, people are rocking out at Willie’s own Heartbreaker Banquet, an annual fundraiser/music festival held concurrently with SXSW. Now 81, Willie is biding his time before joining the festivities, and we’re talking about why he puts on...