We stayed five in a room at RPH in December, 2008. According to the website, we should have been charged extra for the fifth person, but we were not. Our kids (8, 10, DN11) were still small enough they all fit in one bed so we didn't request a rollaway, that may be why we were not charged.
Also, I believe you can book a room now by phone, but that internet booking will not be available until the fall. I'm waiting impatiently, since we are planning a trip for next year also. (Either Spring Break or early summer. Woo hoo!)