The initial error is compounded by our subject and his son, Aaron DAVIS, Jr., being confused with another Aaron DAVIS (c1755- ), who also married a Rachel, but who lived in (W)VA and TN, not New England.  These are two different couples.  It's extremely unlikely that a New England DAVIS family moved to Tennesse in the late 1700s or early 1800s.  The geography on this one shouted, "NO WAY!"; and when the dates didn't jibe, either, it was time to heed the warning and recognize that a mistake had been made.

1.  James N. Arnold.  1891.  Vital Record of Rhode Island, 1636-1850.  Vol. VII. Friends and Ministers.  Narragansett Hist. Publ. Co., Providence, RI. (online at americanancestors.org):

p. 277	Swansey Record of Friends MARRIAGES. A... ANTHONY...      Lois and Moses Davis, 11d 11m 1762.      Rachel and Aaron Davis, 19d 4m 1764...
p. 285	D... DAVIS...      Moses, of Thomas, deceased, and Lydia, of Freetown, and Lois Anthony, of Job and Abigail, of Taunton, 11d 11m 1762.      Aaron, of Freetown, of Thomas, deceased, and Lydia, and Rachel Anthony, of Jonathan and Abigail, of Taunton, 19d 4m 1764....
p. 287	L... LAW, James, of John and Mary, both deceased, of Swansey, and Abigail Davis,      of Aaron and Rachel, of Freetown, 25d 6m 1794...

2.  Ebenezer W. Peirce.  1866.  "The Posterity of William Davis, of Freetown."  New England Historial and Genelogical Register (Boston). Vol. 20 (July 1886): 212-217.

Transcriber's Comment:  the article is written in a sparse, telegraphic style with no introduction.  It begins with the line I show as the first line on p. 212.  Where I've quoted excerpts, below, I made lists of the children because the run-on paragraphs were hard to read.  Boldface added.
p. 212	1.  WILLIAM[1] DAVIS and wife Mary Makepeace had:   (2)  William,2+ born June 11, 1688; m. Keziah Cudworth July 24, 1712.   (3)  Thomas,2+ m. Lydia _____.   (4)  John.2   (5)  Jonathan,2+ m. Sarah Terry, of Freetown, Dec. 24, 1730.   (6)  Remembrance,2 m. 1st Sarah Soul, of Tiverton, 2d, Sarah Fox, of Freetown.   (7)  Joseph.2   (8)  Rebecca,2 m. John Paine, of Freetown, Oct. 31, 1705.   (9)  Elizabeth,2 m. Wm. Cole [of Freetown], had a large family, but I have not been able to learn their names.   (10)  Abigail,2+ m. Ephraim Hathaway, of Freetown, Dec. 19, 1717.   (11)  Anne,2+ m. Robert Evans Jan. 29, 1723.   (12) Hannah,2+ m. William Gage, of Freetown?   (13) Ruth.2      Mary the mother was daughter of Thomas Makepeace, of Boston, and wife Mrs. Elizabeth Mellows.  William Davis was grand juryman in 1697.  He married Mary Makepeace March 1, 1686. 2. WILLIAM2 DAVIS, Jr. and wife Keziah Cudworth had... [ten children]... 3.  THOMAS2 DAVIS by wife Lydia had:   (24)  Thomas,3 b. Oct. 1, 1718; m. Mrs. Hannah Wood, of Dartmouth, 1745; no children as far as I can hear.   (25)  Alice,3 b. Jan 16, 1721.   (26)  Joseph,3 b. Sept. 30, 1723; m. Dinah Cleveland, of Freetown, Nov. 28, 1745.   (27)  Lydia,3+ b. Nov. 24, 1725; m. Peter Weaver, of Swanzea, March 31,
p. 213	1754.    (28)  Benjamin,3+ b. Sept. 1, 1728; m. Lydia Nichols, of Salem.   (29)  Job,3 b. April 13, 1731; m. Anne Soule, of Dartmouth, 1753.   (30)  Moses,3+ b. Nov. 14, 1733; m. Lois Anthony.   (31)  Aaron,3+ b. April 12, 1736; m. Rachel Law.   (32)  Stephen,3 b. July 20, 1738...
p. 216	31.  AARON3 DAVIS and wife Rachel Law had:   (146)  Abigail,4 b. March 4, 1765; m. James Law.   (147)  Aaron,4 b. Jul 30, 1767; m. Lydia Chase of Freetown.   (148)  Lydia,4 b. May 20, 1769.   (149)  Susanah,4 b. April 11, 1771. She was dead and dumb.   (150)  Hannah,4 m. Michael Hathaway, of Freetown, Nov. 1796.
	A check with primary records shows Peirce erred with regard to Rachel's maiden name (see Source 1 above).  The author did not take Aaron's children further.  Nothing is this article indicates anyone moved out of New England, and most remained in Freetown.