Nice article.
I just want to add that the sandstone house you're refering to is actually called "Simpson Cottage" it's also a place to stay.www.simpsoncottage.com.au and there's more history and pics available on the website.
It's not at the Bonnie Vale camp ground.
It sits above rangers hut near the picnic grounds.
The Rangers hut is actually built on the foundations of the Simpson's Hotel, which burnt down.
The Simpson family lived in the sandstone cottage which is now heritage listed and to quote Sutherland Council a particularly significantly historic building.
Story has the deer you see in the park and around Bundeena were introduced by Simpson to make the European visitors feel more at home.
It's shame you didn't include some it your post it would have fitted in nicely. (Although I am somewhat biased)