Hi Amy!!!
There are three Signature Restaurants located along the Resort Monorail Line: Citricos and Narcoossee's at Disney's Grand Floridian Resort and Spa and the California Grill at Disney's Contemporary Resort. Of these three, the one that I would consider taking my four year old to would be the California Grill.
While the menu is definitely geared for adults, there is a good
children's menu at the California Grill. The view this restaurant offers of the Magic Kingdom should also keep your two children interested. There is even a rooftop area that you can go out and watch Wishes that only those dining at the California Grill can use.
With that being said, if you and your husband wanted a quiet dinner together, this would be a great time to take advantage of that by using the
Children's Activity Centers or Kid's Nite Out options that are available for a nominal fee.
Either way, I know that your family will have a magical time!!!
Scott