Had a nice stay at Cheryl's. It's very centrally located in Surry Hills. I walked there from Central Station (although it was almost all uphill, you've been wanted!) and took long walks up to Hyde Park and the Opera House. Lots of restaurants and cafes around her place too.
As others have noted, the entry is through a back alleyway. It was totally fine, but other solo travelers may not be comfortable with it as it's pretty dark.