I went to the ancestry.com family tree section (I do not subscribe. I don't know if it is worth it - is it?). I typed in what I know (born 1817 in Maine) They list a couple Williams of interest - one in Sagadahoc, ME and one in Fanklin, ME (counties, I presume).
Another is listed as born in Charlotte NB. In the 1880 census William lists himself and his father as being born in Maine so the Charlotte, NB is probably out. William's middle name is Ross so the other William (H) is out.
William married Rocinda Farrar of Harmony, ME (I have her genealogy) in Bangor, ME in 1844. I just cannot figure out how a girl from Harmony, ME ends up getting married in Bangor, ME to someone not from Harmony. How did they meet?
Perhaps William served in the Aroostock War in 1838 where he possibly met Yeaton? I have no idea.