Help needed with Robinson & Colbath family

I have hit a brickwall in Maine and I am hoping that there is someone out there with a sledge hammer to help me dent a hole in it.

Heman A Robinson was born in 1818 and his wife Mary Colbath born 1815 in Maine.  They were married in  1837 in Lowell, Middlesex.  They had their first two children Andrew 1835 and Mary 1839 in Maine, (some believe in Saco).

Heman was involved with the cotton industry and he and his family moved from area to area all the time.  The census from 1840 to 1870 has them in Massachusetts, Maryland, Massachusetts, Georgia and then Connecticut.

We lose Heman after 1870 census, but still find Mary, his wife and some of his children in 1880 in Maine.  I believe that Mary might have died by 1900.

The family has also been told the story that Mary Colbath was related to Jeremiah Jones Colbath who changed his name to Henry Wilson and became the vice president to President Grant in 1873.

Can someone please help me find my family.  I just don't know where else to look for Heman and Mary's parents.

Thankyou

Jane from Australia