AS far as I can see Joseph's sisters Agnes and Ann/Nan married at Bovey Tracy and stayed generally in that area. I think Agnes married George Lambshead 30/1/1781 at BT and they had 4 children there and then one at Ashburton.
Ann may have married James Norcot 21/8/1792 at BT and then had ?twins in 1795 who were baptised at Lustleigh 1799.
However I wonder if Joseph's brother John followed or went with him to NT and he is the one in the 1803 census married to Eleanor? (John Snell m Eleanor Ward 18/9/1794 NT)