The ruins of the Fretus Hotel stand atop a hill overlooking Calabash Bay, an arm of Berowra Creek. It is said to have been built around 1900 and abandoned in the 1920's. You can read more about the hotel's history here.
Getting to the hotel on foot requires a hike of just under 4 kilometres through bushland from the nearest publicly accessible road. A fire trail leads directly to the hotel, so it's not a difficult walk, and quite pleasant if you go during the cooler part of the year. There are a few steep hills along the way, but nothing that should be a problem for anyone in tolerable physical condition. I visited the hotel twice, in 2015 and 2016.
There are houses along the waterfront at the bottom of the hill, the closest of which are less than 100 metres from the hotel, but being atop a steep, wooded hillside makes the place seem more isolated than it really is.
The remains of a small stone building stand some distance from the hotel. This was apparently an outhouse.
Virtually all the wood and metal in the hotel are long gone, and only the stone walls remain. Even the walls are starting to collapse in places.
The interior of the hotel was lined with plaster, into which countless visitors have carved graffiti over the years. The dates on the graffiti went all the way back to the 1930's. Unfortunately this little bit of cultural history is gradually being lost as the plaster cracks and crumbles away.
The hotel was apparently a single storey structure, with about a dozen rooms, and a corridor running along the centre of the building. Since none of the fittings remained, I could only guess at the purpose of each room. I couldn't even tell where the bar would have been. I imagine that the establishment must have had one, but none of the rooms looked large enough for this purpose. Perhaps the bars in rural hotels were just smaller in those days.