RustyRick, where is that Waranga site in relation to the main road? From when I last visited the area, I would guess not readily visible...
If you head east from Rushworth to Murchison, you'll see Harriman Rd to the left, with blue signs pointing to Harriman Point. About 500m further to the left is Little Bourke St. This is the access road to the station. Once you get to the head of the track, the site becomes obvious. Just take it easy as there's a couple of houses up there and they don't expect people to be driving up that way.
As a side point, the Shire has started building the bike track over the old formation from Murchison, and they've got to Hammond.