A Rolls Royce no longer gleams in front of Bill Miller’s Castle awaiting the silver-haired legend in his trademark Panama hat. The penthouse-style living quarters he once occupied are uninhabited.

But the rambling, turreted Tudoresque mansion along Route 1 on the border of Branford and Guilford, one of the most distinctive structures in New England, is thriving.

No surprise — considering its present owners, considering what’s in their DNA. There’s “Jan-Jan the Wonder Boy” who as a child regularly leapt off the top rung of a 30-foot ladder into the waiting arms of his famed gymnast father and once walked on his hands down the endless stairs of Yale’s Payne Whitney Gymnasium.

Then there’s older sister Cheri, a former national limbo champion — one photo shows her slipping under a limbo bar supported by two Coke bottles. And the youngest, Lisa, stage-named “Tony Girl,” who wowed with her astonishing balancing and acrobatic stunts.

All three were part of the family act — and not just as child performers at, among other venues, the New Haven Arena, later known as the Coliseum, and Lake Compounce. All three were, and are, integral players in the transformation of a 19th-century horse barn that began in 1963.

In the space of five decades, a gymnastics and dance studio that welcomed 1,200 students at its peak became a wildly popular discotheque which gradually innovated itself into the opulent cathedral-ceilinged event facility that specializes not just in banquets and weddings but everything from conferences and seminars to proms, bar mitzvahs, and even fashion shows.

Not to mention worthy causes. On Friday, May 10, Bill Miller’s Castle will open its doors for a dance party to benefit One Fund Boston, a foundation for the victims of the Boston Marathon bombing, featuring a host of local musicians including Dave Clow of the Taxmen, drummer Bobby T Torello, Donnie Rahl, and the Sin Sisters.

This versatility of use is in keeping with a structure that at once functions as a living museum of New England and a testament to New England ingenuity. The wood from the ceilings? Jan and his father reclaimed it from old tobacco barns in South Windsor sometime in the late 1960s. As for the wooden lamp posts on the deck and inside the anteroom: “They were lying on the side of Merritt Parkway,” said Jan, a young 64 who cuts a figure as fit and vigorous as his father’s. “We got a permit, a flatbed truck, a bunch of guys, and hauled it in.”

It didn’t stop at the Merritt. Until his death at 88 last July, Bill Miller was a fixture at auctions, estate sales, old mansions, churches, and opera houses. The stained glass, the gates? “They’re all pretty much from Yale,” said Lisa, a striking brunette with the energy and drive that distinguished her while directing the gymnastics program in an early incarnation of the Route 1 landmark.

A result of the family’s sheer industry: the effect, while wandering through the Castle, of being transported back in time. Linger under the ballroom’s chandeliers that once graced the old Taft Hotel in New Haven and you might find yourself imagining Ethel and Lionel Barrymore passing through. Study the railings from the Providence Opera House and you can almost hear the faint echo of bravos from the crowd.

Because here’s the thing — and it explains why, in the late 1960s, Cheri convinced her father that the Shoreline needed its own nightclub — “the first discotheque ever in Connecticut,” as Cheri put it. Cheri’s Shack featured a fog machine, professional lighting, and a ballroom so tightly packed that police would admit a person only if another was exiting.

Given this inclination toward forward-thinking risk-taking, it’s no wonder that the three “kids” have boldly acted to upgrade, breathing life and light into the space with plants and flowers, installing a state-of-the-art sound and video system, and modulating the atmosphere from “rustic to rustic elegance,” according to Lisa, amid the bustle of preparation for a wedding the next day.

They have, in short, inherited their father’s initiative, his stubborn insistence on thinking outside the box and not least, his daring. “Whenever he told us to jump from that ladder, we never thought he wouldn’t catch us,” said Lisa who’s passed on her physical agility to her daughters Victoria, a nationally ranked freestyle mogul skier, and Christina, a swimmer and lacrosse player at Branford High School. “We never learned fear.”

Above all, though, it’s the emphasis on hospitality and entertaining that, it’s clear, is in the trio’s blood. One manifestation of which: unlike other venues, Bill Miller’s never hosts more than one event at a time, affording guests full run of the 24 acres of kingdom.

Then there’s this question, specifically directed to brides which, at least in this part of the world, can be answered only one way: Why rent a hall when you can have a castle? Little surprise Bill Miller’s is booking into 2015.

The smell of hay from the original horse barn is long gone but its framework remains intact. The dance and gymnastics center is no more, but you can still see the hardware bolts for the gymnastic rings hanging from the castle beams.

That’s the wonder of Bill Miller’s Castle. Even as it holds fast to its rich history, it’s a Shoreline institution that keeps moving forward.

Visit their website, billmillerscastle.com for more information about the venue. One Fund Boston Dance Party takes place 7:30 p.m. on Friday, May 10 at 834 East Main St., Branford. For more information, call 917-841-7636.