The Dupui ledger supports the contention that Indian corn was a staple food product in the area, being sold some 23 times, in pecks, skippels and bushels, to area residents over the course of 41 years. 

Pricing of the commodity appears to have remained rather consistent at 3 shillings per bushel for multiple decades, until the price suddenly jumped after the Revolutionary War to a rate of 5 and half shillings per bushel.

The second of the three sisters, beans, makes only a rare appearance -- 2 bushels, sold twice (ten years apart), at a rate of a shilling and and half per bushel, and the third sister, squash, only makes its appearance by way of a single entry related to "the hauling of your Pumpkins."

As these three types of food items, typically associated with colonial gardens, in the aggregate have a rather spotty record of sales at Dupui's store, one can hazard the guess that perhaps they were being sold elsewhere in the area, perhaps at local summer faires.  That, of course, would imply that throngs of folk gathered at some other locale on certain days, leaving Dupui's store without a sufficiency of customers on those occasions. 

This is an implication that can quantitatively be assessed.  We begin with the assumption that a local
re-occurring "faire" likely had set calendar dates that probably would have coincided with the last day of each month during the harvest season, namely July, August, September and October.  We then examine the Dupui ledger for activity on a sampling of those dates:
 

By way of these ledger entries, one can tentatively conclude that area market fairs (in which produce such as corn, beans and pumpkins were sold), perhaps became an end-of-month local summer harvest tradition.