Eggheads are kind of neat and your step-daughter will be with you long enough to see them grow. When you crack an egg try to just break off the top. Let the eggshell dry, paint a face, fill with dirt, sprinkle grass seed on top and voila. In a couple of days you will have an egghead with green hair.
If you decide to use the clay sculpting idea, erupting volcanoes are fun to make. Mold your volcano around a small dish containing baking soda. When you are ready for the “eruption”, pour in some vinegar. The vinegar can be dyed with food coloring to make red “lava”.
You should! It’s fun and they make great presents! The Rag Shop (and I’m sure Michaels does too) sells this paint called Gallery Glass that simulates stained glass. Just grab a bottle of black leading paint to do the outlines and then fill it in with the colored paints. It takes awhile to do and it requires some ability to “fill” in the lines, but the outcome will be impressive. I get glass vases from the Salvation Army (they always have a bunch) and then give them away when I’m done with them.
I use Sculpey to make beads. Get two or three colors, take little pieces of each, and then blend them together for neat-o swirls and combinations. Stringing beads together might be difficult with bad vision, but there’s no reason she can’t build a funky mosiac with them. And she can always make other cool things, like tiles to hang on the wall. Just stick it in the oven and it sets. The only thing is that you’ve got to remind her to wash her hands when she’s done. I don’t think Sculpey is very good for you if you ingest it, and it will stain your hands.
Is she very “outdoorsy”? She might like a botanical garden or a picnic at the park.