I'll second Dawn/ EARLY AM. The water and wind are usually the calmest and you wont have a hatch of 36' sport fisherman ( complete with drunk/ rude captains) to deal with for the most part. Check out newenglandkayakfishingdotcom as well. lots of localcape boys there that can give you some pointers. My advice, without getting to specific is to stay away from the surf and stay around the harbors, river/creekmouths etc and you should find fish. You can check in at fishing the cape in hyannis as well. They can put you onto the local bite.
hth