I can highly recommend Lina's place.
The location is fantastic - Gymea is close to the beaches at Cronulla but also on the door-step of the Royal National Park. Lina's place is a short walk to the shops, cafes and restaurants of Gymea and also the railway station, which gives direct access to the CBD.
The house is very clean and has everything you want. The room was a good size - loads of cupboard space , a desk, double bed.
Lina and Michael were great hosts. Very hospitable, warm, friendly.
Overall, a great place to stay - would not hesitate to recommend.