What issues concern you? eg flooding, traffic concerns ( eg trucks on Greenbank Rd , Crowson Lane now and any impacts you have had already), crime, wildlife impacts, roadkil.
What wildlife do you have on your property -focus on the state and federally signoficant species eg koalas, glossy black cockatoos, flying foxes that you may have heard in your area, kangaroos and wallabies.
Quoll sightings have been observed in Rosina Rd (eg 142 Rosina Rd has had 3 different sightings over a few years – one sighting was of two quolls at the same time), and Greenbank Rd , and Crowson Lane. Even if you have not seen one yourself, you should mention that you are aware of this information .
See attached letter template LETTER__TEMPLATE_820GreenbankRd-NORTH-MACLEAN.docx
Remember you can - and should - email your letter to all politicans who may be able to influence outcome