Bros replied:

Austravel,
Heading north from Cooktown to Bathurst Bay along the Starcke Station track the only four places i know of are 1.Cape Flattery (operating silica sand mining, been there quite a few times, beautiful secluded bay, not sure about access now).
2. Starcke River. (camping near the river or at the front beach, sandies, mozzies).
3. Jeannie River mouth. (never been there, someone else may know).
4. Ninian Bay.(part of Cape Melville National Park, been there once, fished pretty well, fresh water in lagoon, don't know how reliable).
If you have been to Bathurst Bay (Cape Melville) before just head straight onto the beach (left) when arriving for free camping. Don't know how long the free camping will last as that part of the beach is part of the now defunct ? Kalpowar Station, which is awaiting a decision as to who gets what. Fresh water aplenty.
On the way to Bathurst Bay via Kalpowar Crossing you can go straight ahead after crossing the Marriott River to Bathurst Heads. (never been there but friends say no fresh water).
As to Princess Charlotte Bay i have no knowledge whatsoever
Hoping this helps in some way.
Cheers,
Bros.

Bros replied:

govo,
If you are who i think you are, i'll give you bloody nissan.
Cheers,
Bros.