Thank you all so much for the great suggestions!!
I think sis and I have decided to go with several of the above. There is a nice black canvas laptop tote at Staples with one wide gusset and internal lap top pocket for "files" or notebook, while the gusset space can be used to hold some gadgets (until she grows into a larger gadget kit, and keeping the tote for more files, SMbook, etc.) It's got 2 big pouches on the front and it locks. It has both a top handle as well as a shoulder strap. (I'm a bag fanatic, the girls have a bag suited for every sport and activity they've ever been involved in.
The stage management book suggested was the first I bought for her when she expressed an interest. That book has been her bible and she's got things highlighted and flagged. She was recently promoted to HS Production Manager and has selected a freshman Stage Manager as her understudy. The first thing she did was to share her book with the new girl on the promise of getting it back as soon as that girl found her own.
Sis will fill the bag with a generous dose of the many gadgets you've suggested here, and some on the gadgets forum, beginning with the Mag Lite and Tape Measures. The light pen is an awesome idea! I'll have to watch for that.
I checked out the SMA site, and I'm sure she will find the information in the public section very interesting. We are just down the road from NYC, I think it will be fun to join in some of the volunteering opportunities posted there. The cost for annual membership is very reasonable, I may get that for her birthday in January.
I never even imagined the thought of an invitation, but I know she would be thrilled to have that opportunity. I will keep my eyes and ears out for that type of opportunity for her.
You all sound like a fabulous bunch of people. I will enjoy staying in touch with the board. Thank you for the compliments. I guess you could say I am enjoying living my life through the new experiences I've been able to give my fabulous girls that were never offered when I was growing up.