Hi Jay&Dee

Late last year I travelled from Vic and crossed all the bridges and ferries up the Murray. A very small part of SA and I travel alone - keep on the move rather than lingering - but you might be able to cherry-pick some ideas from these:

Second half of this post covers Mount Gambier, Kingston SE, Narrung Ferry

https://stevies-wanderings.blogspot.com/2018/10/stitching-up-murray-1-prelude.html

This post covers Narrung Ferry, Wellington, Goolwa, Murray Bridge, Mannum, Purnong, Walker's Flat, Swan Reach, Blanchetown, Morgan, Cadell, Waikere, Kingston OM, Berri, Lyrup

https://stevies-wanderings.blogspot.com/2018/10/stitching-up-murray-2-beginning-at-end.html

This post covers Renmark and Paringa

https://stevies-wanderings.blogspot.com/2018/11/stitching-up-murray-3-end-of-beginning.html

They might notbe what you are looking for, but could provide a starting point.

Also, this bloke - Brett Lewis - has some destinations in SA

https://www.roamingtheoutback.com/category/travel-destinations/sa/

And this magazine article tours the Flinders Ranges

https://www.whichcar.com.au/explore/sa/4x4-back-roads-flinders-ranges

Cheers

Steve