Keen family, Madison county, Davidson county, Decatur county

I am looking for information on Isaac Keen, born 1830 in North Carolina, died 1908 in Arkansas. He enlisted in the Civil War in Madison County, Tennessee and was released in Nashville, Davidson county, Tennessee. Several of his children were born in Tennessee. I believe his father was Elisha Keen, born 1803 in North Carolina, died before 1870 in Decatur, Tennessee, but I don't have a connection except for the 1850 census.

I'd like to find the following:
*Another connection of Isaac to his father, Elisha.
*Land records for Isaac in Tennessee.
*Records of his first wife, believed to be Martha Lofden/Loftin/Lofton, who died in 1866

If anyone has suggestions or is related, I'd love to talk to you. Thank you for your time,

Sheila