I've just seen his 1843 marriage and 1845 death - Totnes Reg district.
There a South Brent baptism for Elizabeth Barnes, 25 Jun 1843, parents Richard & Elizabeth - may or may not be her.
There's an 1863 South Brent marriage, Elizabeth Barnes (father Richard) to a William Andrew Sparkes. South Brent is just down the road, between Buckfastleigh and Ugborough.
I guess you have Richard's widow and daughter Elizabeth in 1851 and later censuses. Richard/Ann (born c.1800) are less easy to find, maybe the Devon Family History Society are able to help.
Philip