Brief update. I found my 3X Great Grandmother's death notice at the findmypast website today. From a newspaper: The Newcastle Guardian; February 29, 1848
Death Notice
"At Alnwick, 17th Feb 1848 Aged 84, Isabella, widow of Robert Todd, hawker of earthenware."
This is within the area they traveled around Northumberland, England and I know Robert sold pottery and earthenware. She was born Isabel/Isabella Anderson.