This is the information I have on Margaret Mounce. Her sister, Elizabeth was my GGGGrandmother. I hope this helps you in your search, but these are only secondary sources that have not been verified by me. If you have any corrections, additions or know of any errors, please let me know.
She is buried in the Bethel Church Cemetery, Blue John Rd, Pulaski County, KY according to Jeff Waters. His notes indicate that her birth and death dates are on her tombstone and intheEvan Roberts family Bible.
Margaret is reputed to have married "Tuckahoe" the heir apparent to the Cherokee Indian Chief known as "Doublehead" ( Indian name Chuqualatague).
From " County Scott and its Mountain Folk" by Esther Sharp Sanderson;
PP 17 "--------------The intrepid Tuckahoe, bronze Apollo of the west and right hand man of Chief Doublehead of the Cherokees, and Margaret Mounce, daughter of John Mounce, stole away to the home of Elder John Tate, in Rock Creek, Kentucky, and were married in a religious ceremony according to the custom and teachings of the Baptist faith."
also PP17 "-----------------It was to this community that came the young brave Tuckahoe, and the sweet, young thing clinging to his arm was none other than the pretty daughter of John Mounce, formerly of South Carolina; she it was who saved his life only a few weeks before. Here, it is said, they lived until a son and a daughter were born. "
From Wayne County, Kentucky, Vital Statistics, Marriages, 1801-1830.
Roberts, Elisha and Margaret Mounce. Surety, Henry Roberts. Married 30 January 1821 by William Summers. Note: "this is to sartify that I agree to gave my Dauter Margret Mouts to Elisha Roberts to be given the Holey State of Matrimoney by John Munts (Mounce)-witness, Henry Roberts."
Children of ELISHA ROBERTS and MARGARET MOUNCE are:
i. RACHEL4 ROBERTS9, b. Abt. 182610,11; d. Abt. 190011.
2. ii. JOHN R. ROBERTS, b. 1827.
iii. JOEL ROBERTS11, b. July 1832, Cambell County, Tennessee12,13,13; m. ELIZABETH STRUNK13, 30 March 1854, Pulaski County, Kentucky13; b. 1835, Whitley County, Kentucky13.
iv. GRANVILLE C. ROBERTS13, b. 11 September 1834, Wayne County, KY14; d. 07 February 1921, McCreary, KY---Bethel Church Cemetery15; m. (1) CYNTHIA ELLON RAINS15; b. 185015; d. 1933, McCreary, KY---Bethel Church Cemetery15.; m. (2) LETTICE B. GARNER15, 29 August 1851, Wayne Co. ,Ky..
v. HENRY J ROBERTS15, b. October 183816,17; d. 16 March 190617; m. (1) SARAH "SALLY" COFFEY18; b. 1833, Wayne Co. ,Ky.19; m. (2) POLLY J. WALDEN20, 01 October 1863, Pulaski County, Kentucky20; b. 184620.
vi. BETHSADA ROBERTS20, b. 03 April 1841, Pulaski County, Kentucky21,22; d. 01 September 1897, Helenwood, Scott, Tennessee.--Marcum Cemetery22; m. (1) WILLIAM ALEXANDER CLARK22, 16 May 1864, Pulaski County, Kentucky; b. 08 August 1845, Worchester, England22; d. 03 March 1907, Pulaski County, Kentucky22; m. (2) HENRY THOMAS CLARK22, 18 October 189022.
About Doublehead---He died (was killed by three members of his tribe)in 1807, so Tuckahoe was necessarily born before that date. He was probably born much earlier, since he alledgedly married Margaret Mounce soon after Doublehead's death, which would indicate that he was of marriage age soon after 1807, when Doublehead was killed. This would push his birth date back about 20 years to 1787.
Since Margaret married Elisha Roberts when she was 21 years old, and Margaret supposedly had two children by Tuckahoe prior to this marriage, her marriage to Tuckahoe would have occured between about the years of 1815, when Margaret would have been 15 years old and 1821, the year she married Elisha.