It depends on how big the open areas are, but if they are small enough that you don't have to actually cross them with quilting to hold it together, I'd outline quilt.
If she just wants the shapes, I would do an outline stitch, 1/4" around everything. It wouldn't be too time consuming....follow up the underneath of one leg, pivot and go down the next leg, stitch in the ditch to hide your stitches going across to get to the next leg and start up again.
I'd use a ruler for it if you're familiar with that technique and a lightweight thread that matched the background. I think it would quilt up nicely.
Watson