Hi everyone
Good news. I've been able to get onto Ancestry.com at last and have found some interesting information:
1860 Census for Samuel Hardin:
Age in 1860: 62
Birth Year: @ 1798
Birthplace: North Carolina
Home in 1860: On South Yadkin River, Iredell, North Carolina
Members: Samuel Hardin, 62
Matilda Hardin, 51
Lee Hardin, 21
Adley Hardin, 18
Mary S Hardin, 14
Samuel E Hardin, 10
Melver Hardin, 8
(I had a bit of a Eureka moment when I saw both Adley(Adlai) and Melver's names!)

Census for 1850
Members: Saml Hardin, 52 (the name was shortened on this record, and his occupation was "farmer")
Matilda, 38 (there's a discrepancy in the age here, as she is 51 10 years later?)
William F., 16
John J., 14
Lindsey B, 13
Leander, 11 (known as Lee in 1860)
Adlia, 7 (mispelled?)
Mary S., 4
Samuel, 1

I looked for a marriage record for Samuel and Matilda. The only one I could find was for a Samuel Hardin and a Matilda McDaniel in 1848, which is odd because they'd already had a number of children by then. It's possible Samuel had been married before, or that they had lived together unwed before finally getting married.

Anyway, I hope you find this helpful in some way. I'll post more as I find it.