Went up for a little family get-together this past weekend and found:
Keltic Kitchen on Rt. 28 in Yarmouth--terrific breakfasts, though oddly the scones were horrible. Particularly nice to sit on the porch, which is open on three sides and, despite being on the heavily travelled Rt. 28, very pleasant.
Red Rose Inn at the very end of Berry Lane, on the harbor with chairs and tables on the lawn overlooking said harbor--ideal for a pre-dinner cocktail. The food was lovely and desserts really delicious, the Inn (which also has rooms) is charming, and the folks were very hospitable. Found this one by happy happy accident.
Brewster General Store was a nice little stop, too.
Just thought I'd share...