I went for an overnight in October. I bought a plate of cookies and cupcakes for my cadet, and he and his roommate were really happy with that. The email covers everything you should pack and know about transportation and places to stay for your family.
I'm lucky I got a really cool cadet, and what I did was follow him to all his classes and during down time we visited pretty spots on the campus or just hung out in people's rooms. You can definitely ask a lot of questions and request to see different places. I got to play on the IOCT which was pretty fun.
If you went to SLE, this is a totally different and more accurate way to see what a cadets life is like. Since I went on a Thursday, I got to see their spirit dinner and a lot of other fun things.