Know Before You Go:
Not that they'd want to hang out in a spa anyway, but kids under 18 aren't allowed. If it's spring or summer, they'd be happier anyway at nearby Hershey Park.
When to Go:
A 30-minute advance arrival is required, but come earlier for all-day access to steam room, showers, aromatherapy room, lounge---and an unlimited supply of Hershey's kisses.