Hi Michelle!
The best holiday experience in my opinion is the
Candlelight Processional held at the America Gardens Theatre in Epcot. It is absolutely fabulous and a "must see" in my opinion. There is a standby line for it, but you might have to wait 2 or more hours to have a chance of getting in depending on how busy the park is on the night you visit. The other option is to go with a Candlelight Processional Lunch or Dinner Package; only select restaurants are available via the package. If you are interested, I recommend going with Le Cellier or Chefs de France.
Another great option is the California Grill on top of the Contemporary Resort. I recommend going there for dinner and having an Advanced Dining Reservation for an hour before the Magic Kingdom fireworks. If you can't get one for an hour ahead, then I recommend getting one an hour and half ahead and just lingering over dinner. The California Grill has its own private balcony where you can watch the fireworks from. It provides a unique perspective and something that i think would be fun during the holidays.
With regards to Rock 'n' Roller Coaster, it is a very intense, but short roller coaster. You go from 0 to 60 miles per hour in 2.8 seconds at the very beginning of the ride. Then there are inversions and a small cork screw. The ride never slows down. I love it, but it is the only attraction my oldest son doesn't enjoy and his all time favorite attraction is Expedition Everest, the roller coaster in Disney's Animal Kingdom.
Enjoy planning and write back if you have any questions!