Sharon, I think it would be a great summer project. She looks like she just needs some elbow grease, a kerosine spa treatment and a lil tender loving care. Besides, think of all the stories you and your dad can share while you work on your gma's sewing machine. You may even be able to find some pictures of your gma and save them in one of the drawers when your done.
Miz Johnny suggested using Evaporust to clean up the rusted parts. I've used it and it does work well (i did not use it on the body).
Here's a you tube demo:
http://www.youtube.com/watch?v=PWQZCJDBe14
I think you'll be surprised how much better she'll look and how much satisfaction you'll get from cleaning her up.
Good Luck!
Judy