Where can you park to fish overnight. Or if you wanna pitch a tent

You can't they lock it up overnight at dusk, but there are multiple Maine campsites Up and Down the River you might want to check out bergheim.

There is no overnight camping at that Park. However camping on the river bed is legal All Along The River. Even on private property. When camping I usually find a safe permissible place to park my vehicle then I kayak to a camping spot of my choice.

I don't think you can.