In his article "Worthy of Investigation: Notes on the Origin of an Uncle Dave Macon Song" (Tennessee Folklore Society Bulletin, LXIV:1 [Spring 2008], pp. 23-27), Paul F. Wells points out that the refrain of "Worthy of Estimation" is drawn from a bit of doggerel that had been repeatedly appearing in magazines and miscellanies since at least 1800 -- A Curious Love Letter that began "Madam, - Most worthy of estimation! After long consideration, and much meditation, on the great reputation you possess in the nation, I have a strong inclination to become your relation."

Wells thinks that Uncle Dave's second line is "And the great reputation I possess in the nation" whereas to me it sounds like "It's a great reputation I possess here in the nation" but whatever, it's nonsense in any case, and not connected to the verses (which themselves are very miscellaneous).