I think the Grace you were looking for is the one buried on 15 Nov 1885, farmer's wife of Chivarloe, aged 79 (see http://www.cornwall-opc.org/Records/parishes/E-G/gunwalloe_burials_1716_1903.php)http://www.cornwall-opc.org/Records/parishes/E-G/gunwalloe_burials_1716_1903.php).
She is listed on the 1841 census:
Transcript of Piece HO107/137 (Gunwalloe) COCP code 137141, Enumeration District 5
Folio 3 Page 1:
Chyvarloe,1,Thomas Freeman,35,,Farmer,In county
,,Grace Freeman,,35,,In county
,,Edward Freeman,12,,,In county
,,Anne Freeman,,10,,In county
,,Grace Freeman,,8,,In county
,,William Freeman,5,,,In county
,,Thomas Freeman,3,,,In county
,,Grace Hocking,,22,F S,In county
,,Richard Hocking,25,,Ag Lab,In county
And had two further children that I know of: Elizabeth Caddy Freeman, and Mary Freeman.The latter married William Hill, and Grace is last recorded on the 1881 census as a farmer’s widow, resident at Mary’s address (1881 Helston, RG11 piece 2323, folio 95, page 10).