Ant-man said..
Lots of good spots at Lake Macquarie (depending on direction) - Coal Point, Rathmines , Marmong, Valentine, Sunshine. I'm biased (and only Windfoil) and prefer Coal Point (anything from the east around to SSW) and Rathmines (S-E). You could probably get away with camping at Rathies if you are self contained.
Myall Lakes is absolutely beautiful but is brackish water so you may struggle for lift (I windfoil there and it's good enough, others love it).
Not sure as you head further north but theres obviously lots of beaches
thanks a lot, very helpful