Here are some maps. First one is of Ontario (with the small inset of Canada) and then a close up of the area where Prescott sits (in the far southeast tip of Ontario, east of Lake Ontario, across from New York state).
Prescott continues to celebrate its British history with a Loyalist Festival each summer. [2012 ought to be extra exciting as it marks the bicentennial of the War of 1812.]
Grenville County Historical Society maintains archives for the area. They have extensive holdings (Mom, we'll have to visit some day) including ancestral information on the Cain and Flagg families (Thomas and Lucinda's families, respectively, and hopefully). O'Doyle (Lucinda's mother's maiden name) is not on the list. She remains a mystery.
entrance to Fort Wellington in Prescott source
this blue church was built in the 1800s on the site of an older church.
grave markers look old and interesting source