This is a tough area to park in during the summer. I don't know of any long-term parking there during the day, unless you are staying at a hotel or a friend's house. There is a parking lot on the left on the hill that goes up to the lighthouse access rd, but I think you have to pay.
At night, I think you can get away with on-street parking, but I'd call the town police first if I were you. I'm not sure if they'll actually tow cars out of the lots at night.
-bd