Yeah have been there a few times, its a great spot but can get busy at holiday times.
The "eastern" upstream end has a large area, called ulupna island, that gets busy, but has drop loos, down stream there are plnty of camp spots along the river, just take a drive! Further again there is a lakes system but i havnt been there as yet. The ony problem is a little creek that as far as i know separates the two "ends" and you hve to come back out of the forest, cross a bridge and head back in. The parks vic website has a downloadable info sheet with maps.