Brian, I understand that the house is Historic and I do respect that. The shingles could be reinstalled to re create the original appearance and too, accomplish her wish in creating more insulation for the home.
Sometimes I feel that the Historic People do not understand that homes can be up graded without damaging and destroying the old look.
There is a point that the two can meet and co-exist.
Do you think that she wants to live in the cold and not have any insulation value in the walls?
I did not read a suggestion from you on her situation. Give me a break?