Although Musgraves' too-brief set was pushed up to leave more time for the headliners, the substantial audience rose to its feet when she was done, bikers and bluegrass aficionados alike.
On the spectrum that runs from country's reverence for the past to its love of the solitary outlaw, Krauss and her longtime band, Union Station, hewed closest to the former, without so much as a drum kit to alter the formula.
But Krauss' sweet, twangless vocals and her taste for pop melodies were more evocative of Dionne Warwick than Hazel Dickens, and her sense of humor - she described dobro player Jerry Douglas' highly polished instrument as a "perfect hunting tool" for its ability to blind prey - was more prime-time variety special than square dance. (She would have killed on The Muppet Show.)
Tradition hasn't adapted to Willie Nelson so much as carved him out his own custom-fit niche. Artists of his stature can be suffocated by their past glories, each must-play hit another barnacle-like encrustation on a battleship hull, but Nelson prefers to travel light: Apart from a grand piano, the rest of his five-piece band's gear could have fit in the back of a van. He treats his old favorites like jazz standards, throwing away the melody lines to leave more room for his unpredictable guitar playing.
And it wasn't just the familiar songs: Even "Band of Brothers," the title track from an album that comes out Tuesday, got the same treatment. For Nelson, they're all part of his past, and he keeps moving into the future.