I have not checked the Briggs message board for a long time, until Jeanne Howard gave me another wake up call on the Briggs/Sweet/Howard connections. The only concrete Howard/Sweet connection I have is my grand father Frank Howard (1891-1945) and grand mother Ravenna Mabel Sweet (1893-1977).
They were raised near Chicago. My Howard line is traced back to John Kennedy Howard (1840-1882) who was raised in Jefferson County, NY married Frances A. Parish of Theresa, NY and moved to Odell, Livingston Co., IL. in 1865.That town is not very far from Gilman, IL where you indicate that Clarkand other Howards lived. Possibly my Howard line is related to yours through the Chauncey Howard and Mary Briggs marriage in Dutchess Co., Ny.
My Sweet line in Western Spring/LaGrange, IL arrived there in the 1890's. They had tried farming in Olivet, Hutchinson Co., SD. during the periodc. 1877-1888. (I notice from some one else's post that there were Briggs in the Yankton, SD area at that time; my Sweets appear to have gone out there with a S. H. LaMunyan whom thet had known in Lake Co. OH). They got caught in the Blizzard of 1888 and left for Western Springs caring for kids with amputated limbs. My branch of Sweets had lived in Lake Co. OH (1830-1874) having come their withfounding families of Mormons (but they broke with Joseph Smith, Jr early on) Before that they had lived in Sodus, Wayne Co. NY (1815-1830). Prior to that they lived in Cambridge, Washington Co., NY around 1800. Line traces back through Benjamin Sweet (1776-1862) who was born in RI.
I am awaiting some input on the Sweet/Howard/Briggs connection from a Helen Spivak. I'm beginning to think that this circle of intermarrying families probably had connections over several centuries.