I'm another vote against removing her stitching. If her stitches aren't showing up that much, they aren't really going to clash with whatever you decide to do on the rest of it, and you could provide a label explaining that she did that part in [whatever the year was] and you lovingly made it into a quilt in the current year.
I'm inclined to do machine quilting, and if it was my project - and she didn't object - I think using the walking foot to sew around the hand-stitched area and then continuing in spirals on out to the edge would be a logical way of getting to completion while keeping the handwork as a feature in the quilt. Spirals just naturally lead the eye toward the focal point.