Knorrit Flat is suitable for families though, as with any area that has water, care needs to be taken. You can camp close to the water or, I guess, up to 70m-80m away from it. There's a swimming hole, one or two places to fish for bass and eels, mens & womens flush toilets and gas hot showers, tank drinking water, a volleyball net (a little weathered) and a large under-cover picnic area. There are large areas for cricket, frisby and other games. Kids can ride bikes but other than back & forth on the track, there's not really anywhere to actually ride to.
When there's been rain inland and the river is up a bit, you can ride fun but docile rapids in a tube or inflatable boat. They're just rough enough to topple the occasional person out of their tube. You drive out of the camp area and head inland a couple of kilometres. Get dropped off by a driver and ride the river back.
The council limits them to 110 people. It's full during easter and christmas, though still not cramped for room. A bit of drinking takes place at those times but probably a little better than most places. At other times, it's not uncommon to have the entire eight acres to yourself. The office sells ice ($5.00/bag), drinks, ice creams & yoghurts, and hires canoes/kayaks.
Each campsite has a steel on-ground BBQ and the sites are massive - though when busy, it seems others may be allowed partially on your site!
There are also seven pitfires. Firewood is provided for free for the purpose of cooking. But for a general bonfire, you either have to bring your own wood or buy from them (not too cheap).
It really is as green and luxuriant as they photos show. Prices are $10 per adult and about $5 per child. Day visitors are charged $10 per car (though large car loads have been known to be charged double).
Hope this helps.