As Tina & Andreas have already posted that is some drive in 4 weeks and I would say “you would see everything but see nothing”. Be aware that across the “Nullarbor” there have been a number of lookouts closed to the public due to erosion of the cliffs. In my personal opinion take time to visit the “Eyre Peninsula” take the coast road from Ceduna to Port Lincoln via Streaky Bay. There are many side tracks off the main road to some spectacular coastal scenery with lots of “free camping” areas. Coffin Bay NP is well worth a visit and if you like oysters try the world famous “Coffin Bay Oysters” really cheap and very yummy.
To save some time you might want to get the ferry across the Spencer Gulf from Lucky Bay to Wallaroo, it will save you a couple of days driving (approx. 600km) and having to drive all the way up to Port Augusta and down again. The cost of the ferry is about the same as the cost of the diesel/petrol if you drove.
See here for further information: http://www.seasa.com.au/
Make sure you try and book on-line to get a discount.
Hope this might help you plan your trip in the time frame you have.
Kind regards, Aussie1