Hi Len!
I'm excited to hear you have plans to experience
Disney's Animal Kingdom Park's newest nighttime offering,
Rivers of Light. It's a beautiful show that celebrates nature through the use of music, water, and lights - I've been lucky enough to see it twice, and loved it both times! The Rivers of Light Dining Package provides Guests with a meal at one of two featured restaurants and premium seating for the show. The seats are fantastic - right in the center!
Like you, I'm planning a Walt Disney World Resort vacation in December. Also like you, I'm waiting to book a Rivers of Light Dining Package for my December vacation. At this time, the Rivers of Light Dining Package is only accepting reservations through the end of October, but hopefully the dates will soon be extended into the following months. I encourage you to keep an eye on the
Rivers of Light Dining Package page for any openings in December. (I'm checking it every day!) On the September and October Rivers of Light schedules, the show is only offered on select evenings, so I would expect future schedules to be similar.
I also encourage you to stay updated by following the Disney Parks Blog and Walt Disney World on Twitter, as they'll have the most up-to-date information about happenings in the Walt Disney World theme parks.
I'm sorry I don't have more concrete information to help with your planning, but my fingers are crossed that we won't have to wait long for some news!
Thanks for visiting the Disney Parks Moms Panel, and have a magical day! - Diane W.