I am not sure any of the following information will help you, but it might give you clues:
FIRST SETTLEMENT: year 1794 By Oliver Luce Hartland, VT - Zernah or Zemah Allen b. about 1750 daughter: Ruth
Ancestry.com:LaMoille, Stowe, VT "Zernah Allen" ' "Zemah: Luce became Mrs. Allen - lived Mansfield area - one child died All of this in the above book- see Oliver Luce.
Soucrce: Gaseteer of Lamoille and Orleans Counties,VT 1883 - 1884 Published by H. Child Mary 1887 see pp 128-132
LDS (Latter Day Saints) website: 1860 US Census: Samuel Allen age 31 b. 1829 VT lived Chariton, MO (borders with Iowa) Lived Prairie Township
another Allen: 1860 US Census Samuel James Allen age 38 b. @ 1822 VT lived Stowe, Lamoille, VT spouse: Mary A b. @ 1821 VT in the 1850 Census lived Huntington, Vt
John Smith Whitehead b. 2 Mar 1796 Kent, ENGLAND died 8 Jul 1875 Utica, Oneida, NY he married Charlotta(sometimes seen as Carlotta and other) LAW they were married @ 1819 probably England came to USa @ 1828 >ENG>USA
Samuel Washington Allen b. 1829 VT and died 1902 Macon, MO buried in Kellogg Cemetery married Charlotte Whitehead (or Charlotta?) married Macon County, MOabout 1866 She was born Oneida Co, NY so you might find the parents of Samuel W. Allen in that location?
1880 US Census: Eagle, Macon, MO
1900 US Census: father b. VT, mother b. Eng - is this Samuel W. Allen?
Richard Whitehead - parents b. England 1900 Census: married StazzzieSears in 1841 in NY
Richard Law Whitehead 1823 Eng died 1901 MO
1850 US census: living with Elisha Herrick (b. @ 1812 VT) Samuel Allen age 21 b. @ 1829 VT MORRISTOWN, LAMOILLE, VT (CADY FALLS) Morristown in 1895 had a population of 75 1870 - Samuel not listed in household of Elisha Herrick.
1870 US Census: S.W. Allen b. @ 1829 age 41 b. VTLiving TEN MILE, MACON, MO spouse: Charlotte age 22 b. NY b. @ 1848 (or Charlotta?) Ten Mile is just north of Macon, Macon, MO
other: Stowe is not far from Morristown, Lamoille, VT . Morristown is the largest town in that area.
Samuel H. Allen b. @ 1796 VT Warfield, Lamoille, VT - 1860 Lived Stowe, Lamoille, VT married Zirmah Allen b. @ 1793 age 67 b. VT they had daughter Rhoda M. Bl @ 1834 Vt
name: Zirman Allen, Zernah, Zemah Allen Ancestry.com: ZERNER LUCE ALLEN b. 1791 Hartland, Windsor, VT
see: Moses Luce - Rev War Vet b. 1763 MA died 1853 Stowe, Vt
other: HISTORY OF ROYALTON, VT p. 399 paragraph 2
"Oliver Luce was the next owner, selling to Phineas Pierce,..... Pierce's Mills paragraph 3: When Huckens Starrs died, the property was divided among his heirs. A daughter of his had married SLUMAN ALLEN and they had a part or all of the saw mill.James Searles...and they are sometimes spoken of in deeds as "Allen's or Searle's Mills"
..."the following year he sold to OLIVER LUCE the saw mill and grist mill, mill yard, dwelling and 4-3/4 acres for $2,00.00. Mr. Luce did not seem to be properous in his business and after putting tow or more mortgagessold to P. Pierce in 1818."
SLUMAN ALLEN MARRIED HANNAH STORRS on 19 Mar 1786 in Chelsea, VT Known children: Sarah and John
His father was Isaac Allen and mother Sarah French of Norwich, Ct
HISTORY OF ROYALTON, VT p. 984:
"Hannah b. 18 Feb 1765 married SLUMAN ALLEN of Chelsea. published 19 Mar 1786. Most of their life wa spent in Chelsea, but Mr. Allen was in Royalton some of the time while Storrs estate was being settled"
There may be some connection to the Allens in those parts of VT and your Samuel Washington Allen who moved to MO.His parents may have died, or they may have had many children and the first son usually inherited the property. As the VT state filled up, sons and families moved to other newer states.