Fish (walk and wade) any of the estuary areas, river mouths, and beaches, particularly on the south side. Tides can matter though as long as water is moving you have a reasonable shot at finding fish. Concentrate on first and last light, or better yet if you are comfortable fish in the dark. You may be surprised! Good luck. If you bring your canoe, there are lots of great trout ponds, though the fish will be deep as the water temps are high now. An hour before sunrise you will probably find a few fish rising, so drift fishing with midges and dries can be very productive.
Call Chris at Fishing the Cape flyshop on Rt 28 in Harwich (Dennisport line), he really knows his stuff.