This one was pretty much in plain sight for any one of thousands of vehicles that must pass it on an annual basis. I'm curious, however, how many actually notice that it's there.
Entry is discouraged by partial walling with concrete bricks. You can certainly climb over them, but it's uncertain whether the floor will support you dropping down the other side.
I don't think there's much inside of interest anyway, but on the bright side, the opposite side of the road features a spectacular view.
Update February 4, 2018:
I have been able to determine that this house belonged to the Halcrow family, and it appears to have contained more than one generation. It is speculated that it was built sometime around 1919, and has been vacant since at least the 1960's.