In the line for the free bus from New York to Chicago, which will not only play host to this weekend's Nato summit, but also to a series of Occupy protests, an 18-year-old homeless boy called Sean has money to burn. Specifically, he has a dollar.

Sean touches a flame to the note and uses it to light a cigarette. "That's debt, and that's what we do with it," he says, grinning to his fellow Occupy Wall Street protesters.

It's one of those braggadocio gestures that probably has as much to do with the presence of an unfamiliar young woman as it does to hatred of the super-rich "1 per cent" whom this ramshackle global anti-capitalist movement set themselves against when they started camping out in Manhattan's financial district last September.

Smoke streams from Sean's fingers. He doesn't listen to other activists, who are already checking the internet on their phones to see if burning money is a federal crime. "I just hate money for what it did to my family," he says. Then it's time to get on the bus.

Funded by the union National Nurses United at a cost of $10,000, this coach is taking Sean, 40 protesters and me on a sweaty 16-hour journey to Chicago. The Nato summit will begin there in two days (after the G8 conference at Camp David, the presidential hideaway in Maryland), and city police have spent millions tooling up in anticipation of major protests against austerity and the global military-industrial complex.

Delegates are protected by ground troops, riot cops. The so-called 99 per cent have a ragtag bunch of high school college drop-outs, wide-eyed activists and war veterans, who spend the journey live streaming to their Twitter followers and making makeshift defensive weaponry out of bits of old junk.

Chris, 21, describes himself as "the electrician". Tucking his hair into a bandana, he explains how simple it is to defeat the Chicago police's infamous LRAD, designed to deter protesters with excruciating sound waves, with balloons full of shaving foam.

Chris is ripping the backs off instant cameras and turning them into temporary flares, designed to peacefully disable police flashlights. It's all a little bit Home Alone. Most of these young protesters have rarely been anything else.

"I saw my grandma struggle for dollars her whole life," says dollar-burning Sean, a high school drop-out who is softly spoken as soon as you get him alone. "My best friends believe that the only way they can make money now is to sell drugs. One of them got killed, dumb s**t like that."

Sean's mother was a drug addict, and he got involved in the anti-capitalist Occupy protests in Philadelphia soon after he left his grandmother's house and failed to find a job, in a nation where 45 per cent of 16- to 29-year-olds are out of work.

"Grandma said I'd never survive on my own," he says, "but I'm not a bad person, I mean, I do what any other boy would do. I'm still here. Being out here [with Occupy] made me a lot more happy, like I wasn't so alone."

Behind me, the only other reporter on the bus is reading The Electric Kool-Aid Acid Test. Anyone comparing this journey to Tom Wolfe's famous jaunt across America with a busload of melodramatically wasted hippies will be disappointed. This bus, with its bland grey seats and built-in TV screens, could be any old National Express coach, whilst furtive fumblings on the back seats and sneaky spliffs shared out around the back of highway service stations make the Occupy Wall Street fleet rather like a high school field trip for a post-hope generation.

The people on this bus have little in common except poverty. They are racially diverse, and range in age from 62-year-old Barbara, who worked on Wall Street in the 1970s, lost her job in September and feels "angrier than ever" about "corporate money controlling government", to 18-year-old Laura from rural Pennsylvania.

Childlike Laura, hopping over the railings at rest-stops to collect creepy-crawlies in jam jars, is travelling with her elder brother Brandon, a long-time Occupier who was in and out of foster care before he became homeless, and who spends the trip annoying people in nearby seats with those modified flare-cameras.

Laura came to New York to bail Brandon out of jail, and they've both been living "on the streets" ever since. You can't help being reminded that there are many ways of being on the streets, and all of them are political.

One of the great arts to being young and broke in America is learning how to sleep on a bus. Folded around and on top of one another or sprawled on the floor, most of these occupiers look rather older than they are.

An activist from Pittsburgh who likes to be known as Fluffy could be 35 but is in fact 20, squinting behind piercings, a thick beard and arms covered in scars from self-inflicted cuts and burns.

"What first got me into Occupy is my mum lost her house to the bank, and she ended up having to go live in a shelter with my 11-year-old sister," he says. "I've been on the street for the past three, four years."

Ask Fluffy about economic injustice and taxation and you'll get a smart answer, but he becomes truly animated when discussing how Occupy has become his new, safe home. "I love the whole family outlook on everything. It's generally family oriented; you grow to love these people as if they were your own flesh and blood."

If the Flower Power generation was reacting against the buttoned-down sexual prudery of its parents, the post-hope generation is engaged in rejecting a culture that promised opportunity, family and security and delivered nothing but hurt, loneliness and debt. If the 1960s were about confronting hypocrisy with hedonism, the 2010s are about confronting alienation with community.

Sometimes all that community spirit can get grating. After three hours of listening to 40 by-now-rather-smelly bus passengers singing a medley of Disney songs and old protest hymns, all that youthful exuberance starts to cross the line from infectious to infuriating. These people have smartphones, but no homes or job prospects. They're on their way to a peace rally where most of them fully expect to be beaten and arrested. What on earth do they have to sing about?

Connection. That's what it's about. From the live streamers chatting with people following the online stream all over the world to the new friendships I see being formed around me, it's all about connection. It's about information shared, about building new codes of care and community where the old ones, the jobs and families and pension plans, have proved unreliable.

"We got a lot of good people in this country," says a 32-year-old who likes to be known as Sparkle, from Brooklyn. "All we want to do is work and be able to support ourselves and be able to live a decent life, and, thanks to the rich being greedy, we can't even have that. So it's not a case of 'You stupid hippies, get a job'. Really? Check my resume. Give me a job."

I hear very little on this trip about Nato itself. Although most of the Occupiers are well-informed on matters of military spending, US interventionism and economic injustice, they are also simply grateful for the free pizza and a warm bus to sleep in.

Up front, the "bus captains", self-appointed team leaders from the nurses' union and other groups, attempt to keep the gang on-message with little rallying speeches. Shen Tong, one of them, is largely ignored when he steps up with a prepared list of talking points for the media – until he leads them in a call of "We are the 99 per cent", at which point the whole bus chants as one.

"We are the 99 per cent." Neither the presidential candidates struggling to incorporate this sudden cultural shift into their message nor the global police forces that have beaten the Occupy movement back with violent evictions, arrests and surveillance really understand what that statement means for people with nothing to lose.

It is a cry for inclusion, for recognition. It is about demanding your place in a society that you thought had nothing to offer you.

A little help from the old guard never hurts. In 1970, labour organisers had so little common ground with anti-war, anti-capitalist hippies that they came to blows, but in 2012, these young people sleeping tangled in blankets in the aisles find themselves burdened with the expectations of the entire American left. So much so that union donors have funded 17 buses from across the country at a cost of $250,000, hoping that Occupiers in Chicago will reinvigorate what remains of resistance to financial feudalism in the United States.

It's a tall order for a fleet of 200 political outsiders and homeless kids. Whatever the Disney songs say, millions of dollars' worth of policing have historically been more than a match for courage and true friendship.

The bus pulls into Chicago. Hot soup and sleeping spaces have been arranged in a local church for the exhausted travellers. Watching them file off the bus into a crowd of waiting journalists, Shen Tong looks satisfied.

Tong has seen all of this before, in China, his country of birth. In 1989, he was imprisoned and exiled after working as a student leader during the Tiananmen Square uprisings. This is not the first time he has watched young people almost broken by society growing up to change it.