Actually, the maths - it adds up to a single show lasting 2 years - seem to be defeating the man himself. The first I heard, it was a year-long show; the flyer says 18 months. But he confirms the longer season.
"What I found in the rehearsal," he tells me, not obviously tongue-in-cheek, "was that I didn't want to rush it."
Monkey is an adaptation of a 16th-century Chinese novel called Journey to the West about a young monk who travels to India to fetch the Buddhist scriptures. His companions include a monkey, a pig and a horse. A captive princess and fierce monsters put in an appearance.
Broadhead says that the 1942 translation by renowned scholar Arthur Waley, which is his source text, is "very Chinese" and the beauty of the language is lengthening the project.
"I keep getting to phrases that are so exquisite that I want to linger over them. I want to stay and let them go into me."
Broadhead's CV runs to at least 60 shows, most of them flamboyant extravaganzas using non-professional performers who never had to audition. "Stages" have included the banks of the Water of Leith in Dunedin, a terraced garden overlooking the Pacific at Papamoa, the concourse of the old Auckland railway station and the Savage Memorial above Mission Bay.
In contrast, an adaptation of Lewis Carroll's The Hunting of the Snark played more than 500 times in private homes for audiences of a dozen or so. The characters were dolls made of modelling clay, and the suitcase he brought them in was the set.
This time, the stage is the large living room of the hilltop home he built with performance in mind. The house, which has bargeboards that curve up at one end and down at the other (he says it reminds him to keep his feet on the ground and his head in the clouds), overlooks stands of taraire, totara and kauri and has sweeping views of the island. He will be the sole performer.
"I don't have the energy to direct those huge things any more," says Broadhead, who will be 70 this month. "Most of the shows I've done have been about pleasing the audience; with this show, the idea is to please myself.
"If the audience gets something out of it, that would be wonderful but the main premise is my enjoyment and understanding of the thing."
At 30 hours (never mind 30 months), Monkey may be the longest show (as distinct from the longest-running show) in theatrical history. But its creator is immune to my suggestion that the idea is simply a conceptual provocation, that he's trying it on.
"What's outrageous about it?" he asks. "How long has Shortland Street been running. Once a night for God knows how many years."
Audiences don't need to come to every episode - although there are discounts for regulars. "I'd love it if you did," he says, "but at each performance I will catch the audience up with what has gone on before."
Broadhead says he came across the story "30 or 40 years ago" and repeatedly tried to devise productions, solo or with others, but the idea had never gelled. On Waiheke, in what he describes as his "contemplative years", he rediscovered the book under the most poetic of circumstances.
Waking from a nightmare, he picked it up and "it spoke to me like it never had before".
The possibility has occurred to him that there may be performances that no one will attend. He smiles, slightly inscrutably perhaps, at the question.
"That may happen," he says, "but I'll do it anyway."
warwickbroadhead.co.nz