Yvonne's appartment is next to Mascot Station and a short walk (20 mins) from Sydney Airport. It is extremely convenient and works well as a base for exploring the wonders of Sydney. The place was clean on arrival, although walls could do with a fresh lick of paint and the staircase needs improved lighting.
Everything worked and Yvonne and Owen were excellent responsive hosts. Another plus is the Meriton shopping precinct across from the Station. Good food at a reasonable price at the restaurants and supermarkets that form part of the Meriton complex. Tip: Walk the whole complex before making a decision about where to eat because the area is large with some restaurants in side streets.
Found that we could use our credit card and/or smart phone pay for train travel so don't stress too much about the Opal card. Also if you don't want to pay the standard $16 per person fee to travel from the Airport to Mascot (1 stop) on the train, you can walk (20 mins).