I went to Cape Cod two summers ago, staying in Harwich Port and in Provincetown. The Cape's beaches are rather narrow, and many are gravelly. Many are private and restricted. I would try hunting the wet sand at low tide, and off-hours at public sandy beaches that are heavily used during the day. I'd avoid the gravel beaches, as rings, etc. don't sink down as they do where there is soft sand. I don't recall seeing any restrictions on the use of metal detectors on public beaches, but as I said, I had no real luck on the beaches anyway and would prefer to go elsewhere. My most disappointing experience was stopping excitedly at an abandoned bungalow colony I espied on the beach outside Provincetown (the beach houses must have been built in the '20s), and finding nothing old or valuable. On the plus side, I saw no other metal detectorists on the beaches during the week I sojourned at the Cape, so you won't have much competition. Good luck.