You could of course make a new fork for it. That way you are not disturbing her bike while you make it better for touring. I'd choose heavier walls like a 1.1mm wall thickness. The kind of stout blades now needed to withstand the forces of disc brakes. Those blades uncut would probably weigh around 200 grams or a bit more. Of course that extra thickness may alter the ride quality a bit. I'm guessing your future plans probably include making her a completely new frame.