One "connection" between Myles and Richard Bowen presented by others is that Richard was from the Kittlehill Farm on the Gower Peninsula. This association is not documented and can be seen as just hearsay. However, Kittlehill is just a stone's throw from Courthouse Farm and the town of Ilston. Myles's Baptist Church, that he vacated when moving to New England, was located near Ilston. This is well documented. The question then becomes are there other connections between Myles and the Rehoboth group that would bring him to Rehoboth? Or did he come to Rehoboth due to his familiarity with the Bowen family from Ilston? Assuming our Richard was from that Bowen lineage, of course.
A piece of data that would support this connection will be to test the Y chromosomal DNA of Bowen men from Wales and especially the Gower peninsula. That is Bowen men that claim ancestry from the Gower peninsula Bowen's of the 1400-1900s. The Y chromosome of the Richard Bowen lineage in the US is well documented to be Y Haplogroup G2a and positive for SNPs: CTS4803+, Z6150+, Z30771+ F3484+ Y36533+ S2827+. The Lewis lineage mentioned above is also a closely related Y Haplogroup G2a that is positive for SNPs: CTS4803+, Z6150+, Z30771+ F3484+ Y36533+ FT360979+. The difference in the Y DNA between these two lineages suggests they shared a common ancestor approximately 650-700 years ago.
Just to stir the pot a little, the following is from p.51 and p.52 from the book entitled Memorial of the Bowen Family by E.C. Bowen, M.D. published in 1884.
Llewellyn ap Owen married, A.D. 1369, Nest, daughter of Howell Fychan, Esq., probably a descendant in direct line of Ednyfed Fychan, ancestor of Owen Tewdwr, grandfather of King Henry VII. Llewellyn ap Owen had by his wife Nest—besides Rhys, ancestor of the Owens extinct, and Evan, ancestor of the Bowens of Pentre Evan, Llwyngwair, Trephloyne, etc., and other children —Philip of Panteg, who had a son Howell, and he a son Lewis (who took the surname Lewis). He (Lewis) married Gwenllian, daughter of Sir Thomas Philips of Picton Castle, knight (fifteenth century), who became founder of the great family of Picton Castle by his marriage with Jane, daughter of Sir Thomas Donne, son of Owen Donne (see Lewis Glyn Cothi's '' Works," p. 30). Of this family was Sir William Lewis (knight), mayor of Bristol, and many other families in Wales. Gen. Lewis, who married a sister of Gen. George Washington, and served under Iiim during the war of the Revolution, is supposed to have descended from this family of Lewises. Many descendants of this honorable family still reside in Virginia and other Southern States.
This implies that a Bowen lineage and a Lewis lineage shared a common ancestor, Llewellyn ap Owen, that was born approximately ~1344. 2020-1344 = 676 years ago.
Awfully close to the 650-700 YBP calculated by the Y chromosome data.
Some of what EC Bowen said about Richard Bowen d. 1675 has been questioned and deemed to have been somewhat fabricated. But, this remark he makes about Llewellyn ap Owen can probably be substantiated with a little effort.