Linda, Rootsweb Family Tree has several listing William and Rachel, that will put you in touch with other researchers:
http://wc.rootsweb.com/cgi-bin/igm.cgi?op=GET&db=boyd-trees&id=I072683
There is also a Bryants's Station in TX, established in 1840 by Benjamin Bryant, but that Benjamin was born in GA 1800, compared to William's son Benjamin born 1797 KY.
Sincerely, Fran Bolton