And he's right. Flanked by towering century old elm and oak trees with almost complete canopy closure, this is as grand an entrance as you'll find in Canberra's suburbs. But for the sound of cars zooming along the nearby Barton Highway and the occasional kangaroo dropping on the lawn, you could easily be excused for thinking you were approaching an English manor in set the Cotswolds, not one of our region's earliest homesteads.

Until the trees matured, the homestead, built on a natural rise, would have been an imposing site from far afield when first built by William Davis back in 1862. But today, completely hidden from the view from passing traffic, it's only as we reach the carriageway loop, that through a grove of Mexican and Arizona cypress we finally catch glimpses of its stately façade.

Shrouded from prying eyes, apart from several generations of CSIRO scientists who have been housed in offices in and around the homestead since 1953, not many Canberrans have had the opportunity to see the historic home, let alone to venture inside. However, as part of the Canberra & Region Heritage Festival, next weekend the homestead's doors will be open to the public for the first time, and today, Palmer is giving me an exclusive preview.

In fact, Palmer couldn't be a more appropriate guide, not only has he worked on this site for the last twenty-seven years, including for the past seventeen years as the Collection Manager of the Australian National Wildlife Collection, he's also a direct descendant of John Palmer to whom this land was first granted.

"John came out to Australia as purser on the HMS Sirius in the First Fleet, and in 1828 this land was taken up by his son Thomas George" explains Palmer, clearly proud of the personal connection.

Finally we emerge from the trees, and standing at the front door and looking up, it's clear that it's a building in two parts.

"The two-story rendered brick Georgian style northern section was built in 1862-65 by William Davis who was manager of Thomas George Palmer's Ginninderra [now known as Palmerville] estate," explains my guide, before pointing towards the much grander sandstone Victorian-style extension, and adding "Edward Crace bought the place in 1877 and transformed it into this country mansion we see today."

Inside, Palmer ushers me up the grand cedar staircase of Crace's stylish extension to spacious rooms with double bay windows overlooking the surrounding countryside. We talk in hushed tones. You just do that in old buildings, don't you? It turns out to be a wise decision as we pass a number of office workers beavering away at their computers. It turns out they are staff of Soldier On, current tenants of the building. "It might be grand, but it's cold in winter and hot in summer," says one staff member as we poke our head into the old dining room, now an office.

The older section build by Davis, who according to Palmer "farmed sheep, wheat and oats," is much less ostentatious. The skirting boards are shorter, the architraves thinner. As we walk around Palmer explains "Davis and his wife didn't have children but they regarded their nephew, Henry Palmer, as their son."

"However, in 1877, distraught by Henry's death at just 24 years old in a horse jumping accident, Davis sold his property to Edward Grace who commissioned the design of the extension five years later," reveals Davis.

The rooms in the older part of the homestead are smaller and darker too, and talk soon turns to ghosts. Well at least it does for me. Ever the rational scientist, Palmer is quick to dismiss the prospect of any poltergeists lurking in this mansion's pantry. "I'm not aware of anyone having the hair on back of their necks stand up or anyone having a harrowing experience in here," says Palmer.

However, aware of you akubra-clad columnist's penchant for things that go bump in the night, he does disclose that our next stop, the cellar, is home to "some interesting folklore".

The cellar is the closest of several outbuildings which include a coach house and maid's quarters in a very pleasant north-facing courtyard.

Carefully, Palmer pulls open the double cellar doors, then wiping away cobwebs, we creep down the old stone stairs into the gloom of the sunken room.

"Folklore says convicts were locked in here" says Palmer, pointing to bars on the shoe-box sized windows which at ground level barely allow a feeble stream of light into the cellar.

Tempering my obvious enthusiasm, Palmer promptly sets the record straight, "Of course, it's urban legend only, for the homestead was built a bit late for the era of assigned convicts," adding, "I think the bars were more a case of protecting the cellar's liquid contents."

Apparently the legend began in the early 1950s when the homestead was used as a residence for Diplomatic students from the Department of External Affairs. Fuelled by the odd student drinking session, I've no doubt the cellar was the scene of many a later night prank.

Back out in daylight, Palmer offers to show me more of the homestead and gardens, but I politely decline. I want to leave some surprises to discover on next weekend's open day, which really is a rare opportunity to gain an appreciation of life during Gungahlin's pastoral past. Just don't mention the ghosts.

Gungahlin Homestead Open Day: Open to the public for the first time, this one-off event hosted by the National Trust features a full range of fun activities, displays and tours. The homestead's current tenants, 'Soldier On' will also showcase the valuable work they do to support men and women who have been physically or psychologically affected by their military service. Saturday 22 April 22 from 10am – 3pm. 44 Bellenden Street, Crace. Gold coin donation. Ph: 62300355.

Don't miss: Ask your guide to show you where the homestead's fixed phone was located – apparently it was the district's first private line.

It's all in the name: The homestead was originally called Goongarline, an Aboriginal word for 'rocky hill' which was later anglicised to Gungahlin.

Bushranger heist: In 1865 William Davis was held up by bushrangers Ben Hall and Johnny Gilbert at Gearys Gap near the current Weereewa Lookout at Lake George. Davis' gold pocket watch, a belt and revolvers were found on Hall when he was shot dead by police near Forbes in May 1865.

Did You Know? On 20 September 1892, Edward Crace drowned with his groom George Kemp while attempting to cross a flooded Ginninderra Creek near George Harcourt's store and Ginninderra Cottage. After Crace died, his son, Everard, managed the property until the Commonwealth resumed it in 1915.

Clue: All aboard!

Degree of difficulty: Easy - Medium.

Last week: Congratulations to Jennifer Harper, of Griffith, who was first to correctly identify last week's photo as "the road sign at Shannons Flat, on the corner of Bobeyan and Yaouk Roads". The location was on Harper's mind, for just an hour or so after she saw the photo in this column she drove past it on her way to the Yaouk Valley, which she reveals "is a wonderful part of the world that very few know about."

Despite Harper's assertion as to the valley's hidden status, over fifty other readers recognised the location, including Lexa Hains, of Ainslie, Margaret M Tie, of Macquarie, and Peter Tozer, of Kaleen, who fondly recalls passing the sign on fishing trips with his dad up into the high country. "Beautiful country and brings back many happy memories," exclaims Tozer.

How to enter: Email your guess along with your name and address to timtheyowieman@bigpond.com. The first email sent after 10am, Saturday April 15, 2017 with the correct answer wins a double pass to Dendy cinemas.

CONTACT TIM: Email: timtheyowieman@bigpond.com or Twitter: @TimYowie or write c/- The Canberra Times, 9 Pirie Street, Fyshwick. You can see a selection of past columns online.