The Eastern Tyers Camp site at O Shea's mill is good but will be full. There are a couple of leech infested campsites near the Thompson River bridge. One has a pit loo.
Also in the area is the state forest Scout camp site which will be full. I forget the name of it but I was with BTAC doing track clearing work in the area. BTAC are going to re clear the walking track along the
Eastern Tyers river walking path now that there is signage and the basic route was cleared 12 months ago.
Here is a weblink about it
https://caravanontour.com/free-campsite ... orest.htmlNorth of Walhalla there are campsites near Aberfeldy along the river in the narrow valley which might appeal to you. The Rooftop's map of the area will offer you more possible informal car camping options.
If you want to carry a pack then the O Shea's mill campsite to Mt. Talbot hike could amuse you. It has a 1300 M. elevation gain. The most of all along the entire AAWT.
Walhalla itself has been turned into a poor man's Sovereign Hill tourist village cum ye olde golde mining area. I remember it fondly before the local version of Puffing Billy was set up as a tourist railway and the village itself was hardly on the tourist map at all . It was FAR less contrived then .There are good rafting options on the Thompson river .