R.F.
If she likes to sew, I suggest a gift card to JoAnn's Fabric, Hobby Lobby, Michael's or another craft store (less stuff to pack). Or a gift card to a national restaurant chain so their first nights in their new house they don't have to worry about cooking meals. For something special, have your son draw her a picture and put it in a little frame for her to display if she opens a new daycare.