We just stayed at Blanket Bay - 20mins past Apollo Bay, for 6 days. We have 2 kids - 4yr old and 8 month old girls and they had a ball! Great beach too - sheltered from waves and a sand stretch for sandcastles. I just wrote up a review in the locations section of here.
Lorne is a nice spot, but can be quite busy. We used to camp on the upper bank of the river but that is all gone now
Airies Inlet is also a nice spot, but I've never camped there (nice beach and river though).