The most visceral and heartbreaking scene in the new Neil Young documentary, Journeys, (which has just finished its run at the Lighthouse Cinema in Smithfield; the DVD is due in June) comes when he performs 'Ohio'.
It's a powerful song whose anger at the state-sponsored violence of the Nixon administration remains undiminished down the decades since it was first appeared in 1971 on a Crosby, Stills, Nash & Young live album.
"What if you knew her and found her dead on the ground?" sings Young.
Director Jonathan Demme intercuts Young's performance with archive footage of the shameful scenes – and then we see the names and photos of the two girls and two boys who lost their lives, each smiling in family snaps or college yearbook pics, none older than 20.
It's the most emotional moment of a film that sees the Canadian guitar god look back on his life and those he has lost along the way. There's bittersweet footage of his long-time crew member, Larry 'LA' Johnson, who died in 2010, playing with Young's severely disabled son, Ben.
And there's a tribute to the late veteran pedal steel player, Ben Keith, who performed on many of Young's finest recordings through the years.
"The people you lose, they're not really gone – because they're still in your head," says Young, reflecting on his departed friends.
The emotional transition from grief to stoical acceptance is only one of the journeys Young takes in the film. His 45-year musical odyssey is another – he dusts off tunes from the 1960s ('Down By The River') and early 1970s (an incredible version of 'After The Goldrush' performed on an enormous pump organ and harmonica) right up to selections from his 2010 album Le Noise.
The film is also the tale of his journey from smalltown Ontario to the concert halls of big city Toronto. It begins with Young driving through his home town of Omemee in north Ontario and stopping off to visit the site of his old family home, long since burned to the ground, in the company of his brother Bob. He reminisces about sleeping outside in a "pup tent" as a kid, the better to keep an eye on his chickens.
Amazingly, it's Young's father Scott who's the most famous family member in the town – the high school is named after his late dad on account of his nationwide fame as a sports journalist.
Then we're back in Young's 1956 vintage Crown Victoria for the trip to Toronto, where he is due to play a solo show in the city's stately, grand Massey Hall – the same venue where he recorded an extraordinary live album almost 40 years before.
Whether he's playing acoustic guitar or whipping up a wall of feedback on his electric Gibson Les Paul, Young remains a force of nature, a survivor who has been conjuring that wild mercury sound from his six-string since before Jimi Hendrix set his on fire.
Yet even now he remains a restless spirit. Last year alone, apart from the solo tour, Young released two albums with his band Crazy Horse – Americana, which saw him cover popular folk and roots standards, and the amped-up, wall-trembling Psychedelic Pill, which featured one jam that clocks in at 27 minutes.
Oh, and he also wrote his idiosyncratic autobiography, Waging Heavy Peace, which details his latest venture: a new kind of audio reproduction system called Pono, which he hopes will rescue music from the tinny compression – and degradation from "soul communication" to "entertainment" – of the digital age.
And the book also documents his campaign to make the dream of eco-friendly electric cars an everyday reality – see his lincvolt website.
All of which whets the appetite when Neil Young & Crazy Horse stop off here on their European tour. They play the RDS Showjumping Arena on Saturday, June 15.
That's one journey I'll be making.