This could be a long shot, but it's possibly worth sharing.
According to several trees online, Caleb Colvin Tubbs was the son of Frederick Tubbs who had a sister named Almira/Elmira who was married to Myron/Miron "Nehemiah" Monroe.
Nehemiah Monroe had one known brother named Ransom. They can be found in Steuben County in the 1850 federal census and 1855 NY State Census (also see it spelled as Munroe).
In Ransom's home in 1860 (Bureau County, IL) is a Joseph H. Monroe, a probable brother or possible cousin, though not yet documented. He is listed again in 1860 with wife, Flora (Winnebago Co, IL). All of these records are documented with data taken from Joseph's Civil War Pension File to prove that the Winnebago Joseph is the same as the Bureau County Joseph, and who has connections back to Steuben County, NY. Joseph and Flora haven't yet been located in the 1850 census, but are expected to still be in the Steuben County area.
Joseph H. Monroe's wife was Flora Ann Harris. They were married in Horseheads, NY according to the 1894 pension file, and Flora lists 3 brothers still living in NY: Jackson, Major, and William. She lists Major's last known address as being in WOODHULL. See my 2010 post here: http://boards.ancestry.com/surnames.harris/14323/mb.ashx
While Harris is a common name, the possible double connection to the Tubbs family and to Woodhull may be a possible lead.
I don't know anything more about that Harris family than what I found in the pension file and through attempting to research them. Should you find anything further, please let me know.