JB-
I grew up fishing the surf in the Dennis-Yarmouth area. I will probably be able to blame my future skin cancer on the spring run of bass and blues on the south side beaches!
Beginning in Mid May, from about the 10th on, there are bass on most of the south facing beaches and inlets. West Dennis Beach, Smuggler's (Bass River Beach), Seagull Beach, and the many beaches of Dennisport will all produce. Memorial Day Weekend always brought the first strong run of bluefish, almost like clockwork. From then on it is great until things get real warm in mid July. After that, forget it. The water is just too warm for beach fishing.
For early July, I would suggest a running tide in the late afternoon into early evening and you should do well. The water does warm quickly as Nantucket Sound is shallow. Blues will hit the beaches often right at sunset especially if there is a decent SouthWest wind blowing, which it seems like there always is!
The inlet right behind West Dennis Beach that runs more or less west and east is a great spot to look for bass. It holds fish all season long.
Chatham is great too, but , like any place, it has its' good days and not so good days. Try doing a search for "Outermost Harbor Marine" who run a water taxi to Monomoy. That would be fun and probably your best shot at whacking fish from the beaches in that area. Although, many guys walk the length of Hardings Beach at the entrance to Stage Harbor and do well also.
I hope this helps you out.
-Hooper
www.melissaannsportfishing.com