When asked, my experienced son says the best advice for Freshmen is, "STAY HYDRATED!" It is so important for students to drink lots of water throughout the week. Also, stay away from excessive amounts of junk food. This isn't to eliminate caloric intake (for surely they will burn LOTS of calories) but rather it contributes significantly to how they will feel throughout the week. Newbies love to bring lots of junk food, experienced ones bring healthier options...or eat the junk more selectively at least.
Another bit of advice. WEAR SUNSCREEN. I know, your student wants a tan. I get it, but trust me, a bad sunburn on day 1 will make you miserable the rest of the week. You will get some sun even while wearing sunscreen.
You are welcome to go out to Hope College and visit during the week if you are curious about what they are up to. Several families will stop by rehearsals at the stadium to see the progress being made. Your visit isn't about seeing your student and visiting with him or her, but rather just watching from the stands. While certainly not a requirement, it is an option that I like to throw out for new band parents.
The community performance on Friday is truly that...a community performance. Invite grandma & grandpa, aunts & uncles, or anyone else who might be interested in coming. You'll be amazed at how many alumni and "non-band" people show up. Though the performance itself is brief, it is amazing to see how much progress they can make in a couple weeks.
Your student will be exhausted. Don't have high expectations for big accomplishments Friday night or Saturday morning. Sleep will definitely be in order.