We–Suzanne, Maleko, Kayla and I — did some walks together between, and just after, the Xmas-New Year period. We wanted to avoid the Xmas crowds gathering around the coastal beaches, and I had used google maps to look for possible ways for us to walk along Hindmarsh River. Most of them turned out to be duds. There were just no walking trails. It was mostly all private property.
One of the afternoon walks that we did early in the new year (2018) was one along the trail of the Hindmarsh River, which ran adjacent to the old McCracken residential development.

It had been years since we walked along the upper section of the Hindmarsh River Walk . On the day we walked the river was low, with little in the way of a flow, and we noticed that there had been some planting on the old flood plain, which was now a park with a playground. The only people that we encountered on the walk were fellow dog walkers. What we found disappointing was that the trail had not been extended further up the river than it had been years ago. It still remained a loop, with a part of the western side of the trail consisting of walking along roads, which was of little use to us.
Another walk that we did together in the week just after Xmas was one along Depledge Rd in Waitpinga:

This was an early morning walk. Normally we walk this back country road in the late afternoon, since it provides shade from the late afternoon summer sun. The roadside vegetation looked quite different in the early morning light.
From what I can gather the Victor Harbor Council does appear to be more interested in developing the various coastal walks–eg. the Heritage Trail or the Encounter Bikeway — at the expense of the ones along the Hindmarsh or Inman Rivers. Presumably, the tourists and those holidaying over Xmas are more interested in exploring the coast than the local rivers.