The Daughters of the American Revolution (DAR) collection includes tombstone inscriptions from Arkansas cemeteries. This collection is described in the "Genealogy" section of this outline.
Another important collection is Cemetery Records of Arkansas, Volumes 1-8, 11 (Salt Lake City, Utah: Genealogical Society, 1957; Family History Library films 908969-71; volumes 1-8, 11 on fiche 6046948).
Many tombstone inscriptions have been published in periodicals or are available in manuscript form at local repositories. A guide to help you locate these and the inscriptions in the DAR collection is Index to Sources for Arkansas Cemetery Inscriptions (North Little Rock, Arkansas: Daughters of the American Revolution, 1976.