James Lapine is working. He looks as relaxed as any other summer resident, bicycling around Edgartown in shorts and T-shirt, but this is no vacation for the Pulitzer, Tony and Peabody award-winning dramatist, theatre director and filmmaker. Mr. Lapine’s new movie Custody, with Viola Davis and Tony Shalhoub, recently played the Martha’s Vineyard Film Festival and his musical-in-progress Flying Over Sunset has a workshop performance tonight at the Vineyard Arts Project.

“It’s something I’ve been working on for years and years,” said Mr. Lapine of Flying Over Sunset. The show is a collaboration with composer Tom Kitt, whose musical Next to Normal won a Pulitzer Prize for Drama, and Tony-nominated lyricist Michael Korie (Grey Gardens). Last summer, the three and their cast presented the first act of Flying Over Sunset in workshop at the Vineyard Arts Project. Tonight’s audience will see the revised first act and, for the first time, Act II.

Mr. Lapine: "I wish I could be here and not work, but I haven't figured that one out yet." — Jeanna Shepard

Briefly, Flying Over Sunset “is about LSD in the 1950s, in New York and L.A.,” Mr. Lapine explained. A magazine article sparked his imagination.

“I had no idea that LSD was legal in the ’50s, and that it was used as a psychoanalytic tool,” he said.

His main characters — all of whom took the drug in real life — are British author and early acid-head Aldous Huxley (1894-1963), Hollywood actor Cary Grant (1904-1986) and, most startlingly, prominent American conservative Clare Booth Luce (1903-1987).

Along with the psychedelic theme (which audiences explored from a different perspective earlier this summer in Larry Mollen’s comedy High Time at the Vineyard Playhouse) Flying Over Sunset is also about the 1950s.

“It’s an era that I find interesting,” said Mr. Lapine, who is 67. “The ’50s were kind of about assuming identities. That’s what brought on the ’60s.”

As a teenager in the 1960s, Mr. Lapine had no ambition to be a playwright or director — let alone screenwriter, filmmaker, librettist or documentarian, all of which he has become.

“I was pretty aimless,” he said.

While studying history at a liberal arts college in Pennsylvania, “I sort of discovered photography then, and so that’s the direction I went in. “It was the hippy-dippy era.”

Following his lens to the West Coast, Mr. Lapine studied design at the California Institute of the Arts (CalArts), the Walt Disney-funded graduate school where his peers included future Pee-Wee Herman actor Paul Reubens. “He was a very different person in those days,” Mr. Lapine said.

An open and collaborative campus where performances were always taking place, CalArts gave Mr. Lapine “confidence to do anything in the arts.”

But still he remained directionless. “I really didn’t have any game plan. I loved California, but I knew I would amount to nothing if I stayed. I’d just be at the beach.”

So he headed to New York city and a series of jobs: waiter, secretary, NBC page and news intern, architectural photographer and freelance designer. He taught at the Fashion Institute of Technology (“They fired me”) and even studied for the bar exam. “I took the law boards and thought if this is what you have to do to be a lawyer, I’m not interested,” Mr. Lapine recalled.

“I just drifted.”

But without knowing it, Mr. Lapine was drifting toward a remarkable career. It began when his freelance design work led to a gig with the Yale School of Drama, where director Robert Brustein tapped him for a faculty position teaching theatre administrators about advertising.

“I loved it there. It was fantastic,” Mr. Lapine said of Yale Drama. His own taste in theatre tended to the avant-garde, but he also wanted to explore filmmaking, just like another photographer, Stanley Kubrick, had done. So when he was encouraged to direct a play at Yale, he took it on as a first step toward filmmaking.

“I thought it was a lark,” Mr. Lapine said. But his production of Gertrude Stein’s Photograph was revived in New York and won his first award, an Obie.

And when he finally made his first film — Impromptu (1991), written by his wife, the Academy Award-winning filmmaker and screenwriter Sarah Kernochan — Mr. Lapine discovered, “I loved the theatre better. Film is very methodical and slow. Theatre’s fast, it’s more suited to my temperament.”

Mr. Lapine may be best known for his work with Stephen Sondheim: Sunday in the Park with George won the Pulitzer Prize for Drama, while Into the Woods was made into a popular film, scripted by Mr. Lapine and starring Meryl Streep, and the fairytale musical is being revived on the London stage this year. He shared a Peabody Award with Frank Rich for their work on the documentary Six By Sondheim.

He is also celebrated for his Tony-winning Falsettos collaboration with composer William Finn. Originally two musicals — March of the Falsettos and Falsettoland — Falsettos returns to Broadway this fall.

Mr. Lapine’s next award-winning musical may owe a debt to the Vineyard Arts Project and Island audiences who have watched his works in progress there. Founded as a dance studio, the Upper Main street, Edgartown facility has been his summer base of operations since he tracked down the management a few years ago.

“I kept riding my bike by and thinking, what is that place?” he recalled. Now on the Vineyard Arts Project board of directors, Mr. Lapine called it his “life’s dream. To live near a place like this so you can actually spend more time on the Vineyard working and bringing actors from New York.”

“I’m really lucky,” he added, knocking loudly on a nearby wooden bench.

New York city residents in the off-season, Mr. Lapine and Ms. Kernochan spend their summers writing in her family’s Edgartown home. Their daughter Phoebe Lapine is also a writer whose blog, feedmephoebe.com, covers “health, hedonism & all the delicious things in between.”

It’s easier to work on the Vineyard than in the city, Mr. Lapine said. “There’s something about the light, the way it’s always changing, it’s playing off the water. It does something to you.”

“I wish I could be here and not work, but I haven’t figured that one out yet,” he added. “But if I have to work, I’d rather be here.”

Flying Over Sunset begins at 7 p.m. on July 29 at the Vineyard Arts Project, 215 Upper Main street, Edgartown. Visit vineyardartsproject.org.