I second the idea of your best book and photos. The pictures will help to give a scale of the production (what sort of tricky set you had to deal with or number of people in the ensemble... that sort of thing) If you want to bring additional paperwork or don't have a book then have an example of what you can do, and probably pull it from one of your more interesting shows because you will be asked about it. Also if you have had experience with something not normally in a high school setting (lots of automation or fancy projections) be prepared to talk about it and if you have paperwork for that bring it along.
I received my BFA from CCM at the University of Cincinnati and wouldn't trade that experience for the world. You will probably get a degree in Stage Management, Technical Theater or Theater with a SM emphasis (or something along those lines) depending on where you go and if you go BA or BFA. When you start getting into looking at schools the piece of advice I can give you is to just make sure you talk to students about their experiences, what they liked and what they didn't, how much they got to SM, what other experience they got that helped them, etc. The professors will tell you what they see as the up and down sides of the program, but the students that live it every day may have a different take.