I believe John Allen (b. 5-26-1806, d. 5-10-1878)& Sarah Crawford are my g-g-g-grandparents, too.They are in the 1850 Randolph County census. (check familysearch...it's a good site)Their son Samuel Tilden Allen (born 1-6-1830)is my g-g-grandfather. They also had a son John Alvis, or J. Alvis Allen. Samuel moved from Randolph County to a farm straddling the Moore/Montgomery County line in 1858.About 1866 moved to Christian County, Illinois near Pana...died 1886.His son was John Daniel Allen (1854-1936).
What I'm not sure of: Sarah's maiden name, or John's middle name.
Let me know what you think...but I see your post is over 10 years old!