You may want to make sure to ask for lots of extra blankets. I had to sleep on an air matress at WDW once, and was always cold. The air matress doesn't keep you warm like a normal bed does. Of course, I'm always cold no matter what, so I'm sure that had something to do with it!
Can't help on the space issue though, we stayed at the Wilderness Villas. Mom and Dad had the master, Brother1 and his family had the 2nd bedroom, and Brother2 and I had to share the living room. So I let him have the couch and I slept on the floor. What are sister's for!