I am a bit confused here and would appreciate members help

We are a family of 3 in our mod 30's and girl child aged 10 years and quite active. We are from Karachi a hot city and like to travel for 3 weeks in a year. We are visiting Australia for the first time

I have my brother in law living in Melbourne so we would be staying there more and would be arriving and departing from Melbourne

Our almost confirmed schedule is as follows
Arrive Melbourne June 24(relax and meet relatives)
Arrive Sydney on June 28 (for 4 nights)
Arrive Gold Coast on July 02 ( we love theme parks and would stay for 5-6 nights)
July 07-12 is still a blank

We need to arrive back in Melbourne to visit (Mt buller , GOR and family) on July 12. As we depart back home on July 20

We are not into history and wine tasting & desserts. We would love a beautiful drive , scenic spot, mountains, lakes, green hills and natural beauty.

This means we have 5 days and confused between the following choices
*Blue mountain and maybe add Southern highland, walanggong or only BM for 2 days
Or
Tasmania for 5 nights
Or
Adelaide
Or
Any other option which the forum can suggest

Fodors have always been a great helping hand in making my trip and I am sure this time all it would turn up with great suggestions and ideas

Have you booked domestic flights ? The Blue Mountains and other scenic drives are close to Sydney. Could you push back arriving GC to say July 7 ?

Alternatively, there are scenic mountains in the Gold Coast hinterland, or head to Sunshine Coast hinterland for similar.

Domestic flights are not booked yet and yes we can adjust the dates

Can I have some more input on scenic drives around Sydney which I may combine with BM

Which one would be better and more scenic in July , in and around Sydney or GC

Or some time to be spent in Tasmania

Don't forget it will be winter here, and very cold for you. The further south, the colder it gets, I'd save Tassie for another time if it were me. Have a look at the report by Yestravel, they spent some time in the Southern highlands just south of Sydney.

The difference between Sydney drives and Gold Coast drives could be about 10 C.
Another thought if it's within your budget...fly Sydney to Uluru for 4 or 5 nights, it's perfect timing weather wise and will certainly be warmer.