I'm more familiar with the outer Cape and the Falmouth area, but I have fished the mouth of the Bass River on the W. Dennis side. The beach on the Yarmouth side might be even better. River mouths fish best on the ebb tide.
Great Island (W.Yarmouth) always looked good to me as a "point" like that is an obstruction on an otherwise featureless coast that traveling fish can't help but run into.
It might still be early for young of the year bait fish, but you may find bluefish corralling peanut bunker back in the estuaries. A kayak would be good for exploring such places. Don't forget the wire.
At night, try around structure with a big bunker fly for cow stripers
This is about the time of year that the pelagics begin to show. The bonito are usually first. Out on a breakwater is a good place to look but don't chase them. They hunt in a pattern and will swing back if you're patient.
On the bay side, I've done really well wading out to the drop off on the flats off E. Dennis.
The only problem for the Cape Cod wading fly fisherman this time of year is the beach parking fees. At 15 bucks a pop it can get expensive if nothing is going on and you decide to move. You're probably okay if you plan on fishing after the beach is officially closed, but I've been ticketed so it's something that I keep in mind.
Don't forget that you now need a marine fishing license.
According to On The Water magazine, the bait du'jour is butterfish and apparently someone caught a sailfish in the Canal on Tuesday