South west wise, what about Penmarlam on the Fal. Has its own slip but you’ll need to book early.
Isn’t Penmarlam at Fowey? ISTR a good site, but steep slipway.
Also on the Fal you can leave your boat at Loe Beach or Mylor for the week and camp at the excellent Carnon Downs campsite.
There’s also Cosawes camp site near Mylor, perhaps not quite so luxurious but it used to be more reasonably priced. It’s been a while though…