Michael,
Well have you had any luck lately? I do know that Helen Hall's house burned in 1999. Unfortunately its possible that whatever personal file Captain Roy Hall may have had on Bill Wilson went up. However,I would also suggest contact the North Texas History Center in McKinney. I do recollect that Helen gave them much info over the years. But,much of the History Center's priceless documents were destroyed by rain a few years ago. In order to make temporary room for a remodel of the museum they put all the documents in a rented storage unit and the roof leaked!