The Parents of Rachel Thompson Born Wiscasset Lincoln Maine USA 1784

She married Oliver Whitcomb on the 5th March 1809. He was born 5th Nov 1784 in New Hampshire. They had several children including Tryphosa P. Whitcomb,Born 15th Nov 1812 in Dresden Lincoln Maine and died 1865.
I think there is a link between Rachel Thomson and Isaac Thompson born 23 June 1800, Lewiston Maine, died 1864 Waldo maine who married a Rachel Moody and had a daughter ..Tryphena Thompson.
All conjecture but no documentary proof of Rachel Thompsons PARENTS!
Any suggestions?
Would be greatly appreciated.