“Truckin’s in my blood,” sings Slim Dusty early into this four-disc compilation of songs devoted to that single road-ready theme. Until his 2003 death, the country icon spent decades laying down tracks about Australia’s expansive outback highways, often cataloguing the colourful characters (and critters) encountered along the way. Sittin’ On 80 also features the previously unreleased “Give Me Room”, cut in 1997 with members of his trusty Travelling Country Band but only discovered by his widow Joy McKean in 2009. It’s an especially frisky entry in this extended showcase of Dusty’s treasured subject, flexing his firm grasp on a classic country sound that never seemed affected by passing eras or trends. A breezy raconteur of the road, he feels like a favourite uncle holding forth.