Military records for the American Revolution are far from complete. There are just three major sources for discovering who actually served during the war. First, are lists of veterans compiled by each state early in the 19th century. Second are the federal pension applications filed by veterans in 1832. Last, are the records of The Daughters of the American Revolution, which detail the military record of members' ancestors.
It is difficult to characterize a "typical" Continental Army soldier, or to ascribe to him particular motives for service. Peter Oliver, a loyalist friend of Thomas Hutchinson, interviewed a captured American lieutenant after the battle of Bunker Hill and published the soldiers comments in an unsympathetic history of the revolution called, The Origin and Progress of the American Rebellion. The soldier said that he had enlisted because some of his neighbors "who were no better than myself" had joined and been commissioned as officers. "As to the Dispute between Great Britain & the Colonies, I know nothing of it; neither am I capable of judging whether it is right or wrong."
200 years later, historian John Shy researched this same soldier, whose name was "Long Bill" Scott. As it turned out, Scott escaped from the British in Boston and rejoined the American army in New York city in 1776. He was captured once again, escaped once again, and rejoined the army in 1777, this time bringing along a company of his own, recruited in his native New Hampshire and including two of his own sons. Scott subsequently fought against Burgoyne in New York and took part in fighting in Rhode Island.
During the war, Scott lost one son to disease and had to sell his farm in order to meet expenses. The money he made on the sale of the farm became essentially worthless during the course of the war as the 1777 dollar for which he sold the farm, became worth less than 2 cents by 1780.
His wife died during the war leaving 3 young children, who Scott had to put in the care of his sole surviving eldest son, while he sought a pension from the government. He had been wounded 9 times during the Revolution.
While no record exists of Scott's sentiments beyond that reported by Oliver, it's probably safe to assume, that they were a little more complicated---or at least had changed drastically---from that post-Bunker Hill interview.