I stayed with Michelle and her family for 8 nights as I needed to do some research at the State Records. Everyone in the family made me feel welcome right from the beginning: we had dinner together, they showed me the neighborhood and we even visited the Blue Mountains together.
St. Clair is a nice and quiet suburb, but if you do not have a particular reason to visit it, it's not in an ideal location to explore Sydney/New South Wales if you don't have a car.