Land was the biggest driver behind your (non-officer) ancestor’s decision to serve in the militia versus on the Continental Line. In the colonies, land ownership was heavily tied to agriculture. Farming requires oversight, especially New England’s smaller farms. A farm owner would have wanted to onsite as much as possible. Militia service demanded – at most – a few months away from the farm. Continental Line service tended to require years: some served up to 6. If your ancestor was not an officer, they likely joined for the advantages of a steady paycheck and a chance to save some money in addition to patriot sentiment. Continental Line soldiers tended to be poorer than those of the militia.
This pattern tells us where to look for the records of the Revolution’s less wealthy veterans. Men of color and those white men without land tend to have served in the Continental Army. Many should be documented in muster rolls, bounty land grants, pensions, and other records of the Continental Line.