If effort/outcome ratio for blender is on the steep side for your granddaughter, have a look at Muvizu http://muvizu.com/ http://muvizu.com/, it's no blender fo

If effort/outcome ratio for blender is on the steep side for your granddaughter, have a look at Muvizu http://muvizu.com/ http://muvizu.com/, it's no blender for sure, but it makes getting started with timeline based 3D animation a breeze (pre-designed scenes, ready to go character animation, special effects, lighting, multiple cameras...), and it's free.