Addressing a hand-picked group of local dignitaries, Blue Mountains tourism royalty, friends of the owners and media, the opulent Wintergarden dining room and the sweeping Megalong Valley just beyond the curved wall of floor-to-ceiling windows, said it all really.

Like so many people, Premier Baird, who's 46, has his memories of the Hydro, coming up to the mountains as a kid and seeing the white building with its beguiling blend of Victoria, Edwardian and Belle Epoch design stretching for more than a kilometre along the escarpment at Medlow Bath.

As did Huong Nguyen, who with partner George Saad bought the building in 2008 for $11 million and set about transforming it for the next six years to the tune of $30 million. Huong's family were Vietnamese refugees, arriving in Australia in 1975 during the first wave of "boat people" – and her early memories of life in Sydney were day trips to the Blue Mountains.

My own memories are of the awe I felt looking at the building's fanciful facade and captivating mountain views, only to be bitterly disappointed when I stayed in the 1970s to find a room rudely furnished with steel hospital-type beds, chenille bedspreads and threadbare carpets, and a walk down the hall to the bathroom to top it off.

Those horrid memories are well and truly banished.

Mr Baird lauded Ms Nguyen and Mr Saad for their passion and dedication in bringing the long-waited Hydro revival to reality. Ms Nguyen quipped they almost left the project in the "too-hard basket", so harrowing was much of the preparation and heritage paperwork involved.

Luckily she didn't. The refurbishment is jaw dropping from the Casino foyer under the iconic dome (no gaming tables here, just Belle Epoch elegance) to the Chinoiserie decadence of the Salon Du The and long corridor known as Cat's Alley. With red walls, red leather dining chairs and lavish turquoise, gold and red velvet sofas and peacock-feather-edged drapes, this is bold design at its best.

Interior designer Peter Reeve sought to bring back the spirit that inhabited the Hydro in its heyday, when the hotel was the place to party in the Roaring 20s and the likes of Dame Nellie Melba sang under the Casino dome.

Four of the hotel's public rooms are open, with the Belgravia wing of 55 guest rooms (about half with valley views) to open on December 23. Salon Du The will begin serving yum cha and an exotic menu of teas in December, while the Boiler Room cafe (created in the room that once provided power to the hotel) is about to open its doors.

The owners are also pinning their hopes for a major tourism boost on the Majestic Pavilion – a brand new building that will host local food providores and offer tastings of Blue Mountains produce in the style of the famous pavilions of the Royal Easter Show.

And to make sure that day trippers turn into overnight guests, Ms Nguyen has a stellar line-up of Aussie legends to take to the stage in the grand ballroom including James Morrison, Richard Clapton, Joe Camilleri and Ross Wilson.