Work on Rufus D. Stephens is slowly progressing.
Rufus D. is one of three adjacent households in the 1850 Census of St.Clair County, Michigan:
Interestingly enough, I just discovered in an online 1842 Yarmouth Township, Elgin County, Ontario, census that both an Arvin Butler and Rufus D. Stephens were living in that locality. This means that they were neighbors in 1842 as well as 1850. Benjamin could have not quite been married or not yet in his own household at that point in time (given the ages of his children in the 1850 enumeration above).
Searching for the neighbors is helping on this one--stay tuned.