Mangy old dope-smoking Willie Nelson, with his grizzled face and creepy braids, is far from a natural fit for the Kauffman Center. (And it will definitely be interesting to see if anybody gets popped from this show for smoking weed.) But the man is a country legend, and when you reach legend status, your lowbrow qualities have a way of becoming highbrow-friendly. Nelson’s latest is called Heroes, and it’s a mix of new material and old covers. It’s also chockablock with collabs, including Kris Kristofferson, Merle Haggard, Billie Joe Shaver, Sheryl Crow and, oh God, Snoop Dogg.