Hidden a block away from the river between two houses. Excellent lobster roll (technically a sandwich, on buttered, toasted bread), light on the mayo. Picnic tables, no frills - just very, very fresh.
Stylish and well curated wine / beer / provisions shop in Central Square. Give them 24 hours notice and you can rent an expertly-stocked picnic basket. And do not miss the Mast Brothers chocolate bars
Best cornichons in town! Used to love to buy them with a loaf, cheese, salami, chocolate, and fresh ground coffee!! Makes a perfect picnic... And pick-me-up when you get home.