Josh slips me a tie pin under the clock in Grand Central Terminal. "This [will] help you channel some of the Don Draper vibe," he says, as New York commuters wash past us – a blue-grey torrent surging across the polished marble floor.
Thankfully, like Mad Men itself (the award-winning TV series set in fictional 1960s advertising agency Sterling Cooper), Josh's tour of Manhattan is stylishly slower paced. As the famous clock moves past 7pm, he leads us across the concourse to begin our induction into the world of Draper and his immaculately dressed, obstreperously behaved cohorts.
"We will be stopping at some upscale establishments, so please dress accordingly," my email confirmation had said. "Sixties-style clothing is encouraged and fun." The others in the group – three female fans in their mid-20s – had taken this to heart, sporting silk blouses, pencil skirts and thick red lipstick.
None of them would look out of place in the Sterling Cooper offices. Josh and I, hair slicked down, are both wearing slim-fitting suits, skinny ties and pocket squares. As a group, we look like we're en route to a 1960s wedding, two generations too late.
Our first destination, the Grand Central Oyster Bar (oysterbarny.com), doesn't even involve stepping outside. Hidden pearl-like within the terminal, the 100-year-old Oyster Bar reopened last month after extensive renovation work, but retains its timeless elegance.
"Matthew Weiner, the show's creator, says when he's writing episodes he's constantly asking himself, 'what would Don do?'," says Josh. "That's something we like to channel too."
A round of old-fashioneds later, Josh whips out an iPad to show us a scene from the show set here. In it, Draper and senior partner Roger Sterling down oysters and martinis, shortly before Sterling regurgitates his meal at the feet of some potential clients.
The series itself is now filmed almost entirely in Los Angeles, but locations are obsessively researched and recreated in fetishistically accurate sets, right down to the tablecloths and framed pictures on the walls.
Sadly, there's no time to stay for a round of oysters before heading to our second stop: the Roosevelt Hotel (theroosevelthotel.com) on the corner of nearby Madison Avenue.
One of the most regularly referenced locations in the show, it's here that Draper comes to live in season two, after his first wife Betty kicks him out. Slippery account man Pete Campbell follows suit at the end of season six, a few episodes after the two men's ill-fated pitch to Heinz in one of the suites.
Over cocktails at the hotel's Madison Club Lounge, Josh plays another clip – this time of art director Salvatore Romano on a clandestine date with a male client in the same spot. Again, the recreation of the locale is unerringly accurate.
Skinny ties are already being loosened as we move up Madison Avenue to take in the Advertising Walk of Fame, and learn about some of the real-life executives behind Weiner's characters. In particular, the legendary Mary Wells Lawrence, who rose from secretary to chief executive in the hard-drinking, misogynistic environment of 1960s advertising, and on whom the character of Peggy Olson is supposedly based.
Unsurprisingly, the imminent seventh and final season is the talk of the evening (so skip to the next paragraph to avoid a potential spoiler).
Weiner is notoriously protective of his storylines – allegedly removing the Romano character after the actor who played him, Bryan Batt, revealed too much – but speculation is rife that Draper will die in the final episode, possibly by throwing himself out of a window on to Madison Avenue.
"The clue has been there in the title sequence since the very start," says Josh. "But I hope Don finds some kind of redemption instead, especially after hitting rock bottom at the end of last season."
The conversation moves on to Peggy Olson as we arrive at the Monkey Bar in the Hotel Elysée (monkeybarnewyork.com) – the setting for her tryst with Duck Phillips in season three. Jessica, one of the women on the tour, is convinced that we're going to see Olson surpass her mentor Draper in the final season, emulating Mary Wells Lawrence by becoming the head honcho.
After a detour to the site of the original Sterling Cooper office from seasons one and two, our final stop of the night is PJ Clarke's (pjclarkes.com), one of the oldest bars in New York. Olson and her cronies are seen here dancing the twist after landing a big client, and Christina Hendricks – the actress who plays office manager Joan Harris – is rumoured to be a frequent visitor in real life.
The Mad Men-approved drink of choice here is a martini and sidecar – "one part sweet, one part sour, one part strong". But thankfully it also serves "the Cadillac of burgers", named by Nat King Cole, who was a big fan of the house cheeseburger.
The Mad Men tour, which Josh's company runs every Thursday and Friday evening, officially comes to a close at 10pm, but at 11.30pm we're still sitting in PJ Clarke's debating the show. It's been a genuine treat experiencing the real-life venues behind the whisky mist of what Rolling Stone magazine recently hailed "the greatest TV drama of all time".
But when Josh suggests a final martini before heading back to the Roosevelt, I'm caught in two minds: What would Don do? – © Guardian News & Media 2014
The trip was provided by the Mad Men Experience (madmentour.com, evening tours $150 including cocktails, daytime tours $59). For further information on New York, visit nycgo.com