In my files, I recently found a Bryan County, Oklahoma map I believe shows the Kemp Family Cemetery along Red River southeast of Kemp OK that the ladies apparently found and tried to describe a route to it (in Find-a-Grave). This map's cemetery location is consistent with descriptions provided on the Second Kemp Ferry site (sons' ferry) noted in the history of Mulberry, Texas. This second Kemp Ferry was downriver (1.17 miles at N29E) from the cemetery site, according to my Google Earth scaling.
The cemetery is located only 1.5 miles east, and 1.5 miles south of modern Kemp OK. After going east from Kemp 1.5 miles along CR E2240, take Tombstone Road south one mile. There, a section line road (Indian Trail) goes east about half-mile to a ranch house and toward the cemetery. No public access to the cemetery, located about 1/2 mile to the southeast of the end of the road, seems to exist. The cemetery was originally located on high ground in the southeast corner of an old Kemp field. The front gate to the cemetery lies on the north side of a 1/2 section line going immediately (about 200 feet) east into Red River. It is only about 125 feet southeast of the front gate to the cliffs (stabilized by a man-made tree line) of Red River.
Kemp Family Cemetery at GPS (33 d 44 m 38.12 s N, 96 d 18 m 36.44 s W ). May they R.I.P.