I don't know if this willhelp you or not, but though one of my connection/links, I found a thomas Atcherson, b about 1749, married an Agnes (unk last name). they married in Boston around 1779. thomas died in Rockingham, VT on June 15, 1830. they had a daughter named Sally (Sarah) b. Oct 2, 1784 in Windham, NH, d. Mar 24, 1861 in VT. There were other children, alexander, thomas, Jane and william.
Sally (Sarah) married a benjamin Phippin in VT, they had a daughter Jane, b. Jul 29, 1828... etc.
there are no parents or other info on Thomas or Agnes. There was a Thomas Atcherson from Southampton, England who was born aroun 1890, migrated to american May 4, 1928... may be some link???
Anyway, maybe you can use this to search ancestry. com as I do see some info out there for this Thomas and Agnes.
p.s. some great links on google for the Fifth Regiment and their battles around Boston.