Banking/Credit Card: research your banking/atm options. Also, we’ve found it useful for our D to have her own credit card at school, so you might want to look into that, too.
Health insurance: check to see if your current insurance will cover your child while he/she is away at school. If so, you are probably able to waive the school’s health insurance.
Moving: figure out the logistics of getting your child to school. If you’re flying, you might want to check into something like Bed Bath and Beyond’s program where you pick out your things locally but pick up your items in the store closest to the child’s school.
AP credits: if your child’s school accepts AP credits, make sure you send them to the school in a timely manner.