I was fortunate enough to recently purchase the two volumes of "Skowhegan on the Kennebec". I have gone through it, however, it doesn't really address the later generations.
I have exhausted, I think, all online sources, and hoped someone on this forum might have some additional data.
My Steward line descends down from "Dr. Bill", William Steward who wrote the marvelous book "The Healing Art or the Art of Healing". When I was in Maine a year ago I saw the original book at the Univ. of Maine in Machias. When I returned to CA I found that a copy was in the U.C. library at Davis, CA. They photocopied it for me - not too great, but at least its readable and fabulous reading.
From Dr. Bill my line descends down through William Steward who married Ruth Gray Emery and then to their dau., Sarah Ann Steward who married Stephen F. Grover.