Hi, Tammy!
You're going to have such a great time at Walt Disney World during the holidays; the Wilderness Lodge is one of the most gorgeously-festooned Resorts on property!
While your son will need to use the sleeper sofa - either folded in or pulled out to create a more traditional bed - you do have the option of bringing an air mattress or purchasing one in Lake Buena Vista when you arrive. Bear in mind, though, that you will also need to bring your own linens for that portable bed.
Florida weather in December is just beautiful. Highs historically are in the mid-high 60s, while the lows are in the low 50s. It doesn't rain too much during the month, either, so your chances of being caught in a deluge are pretty slim.
On Christmas Day, you'll have a wide variety of dining options, of course, from character dining to quick service. If you are looking for a traditional turkey-and-dressing dinner, try the Liberty Tree Tavern in the Magic Kingdom; for an elegant meal, consider Artist Point in your home Resort. Feel free to send me more information directly through
www.DisneyWorldMoms.com as to your itinerary, palate, etc., and I'll be glad to make some more suggestions.
Because we are in the 180-day window (it's 74 days away!), you might want to call (407) WDW-DINE to see what is available for your party. That might wind up making the decision for you!
Have a wonderful trip!
See you later, celebrator!
-Deborah B.