And for down south you have Lake Brockman (loguebrook Dam)
https://www.google.com.au/search?q=l...m=122&ie=UTF-8
Clean pit toilets at the picnic area and $7 per person per night (from memory).
Further south you could go to Alexander Bridge but I can't remember if there were toilets or not, it is a nice looking camping ground for $5pp/pn,
http://www.wanowandthen.com/Alexandra-Bridge.html
But you would really have to be there first thing Thursday morning to get a spot.
There is also Sue's Bridge camping ground on Sue's Road but it is nowhere near as nice. Or Malloy Island Caravan Park further south but tbh I think the dam would be the best bet as it is closer, there is so much room you would find a spot easily and there is really good wheeling around there.