Hi there, Jessica!
Thanks to this question, I went back and did a bit more digging into the roll-a-way bed situation.
In fact, roll-a-way beds
are available. However, they are designated for a particular scenario: when a Guest has two children of different genders that are not to sleep in the same bed, a roll-a-way bed can be provided.
This cannot be arranged in advance, and is entirely at the discretion of the Resort. The Cast Member at check-in will do a visual confirmation of the travel party to determine the situation, and pending the makeup of the travel party, will arrange to have the bed sent in.
A roll-a-way bed will not be provided for an infant; a Pack-N-Play is the only option available. Air mattresses are not permitted due to fire code restrictions.
The Royal Rooms at
Disney's Port Orleans - Riverside Resort are designated for an occupancy of "four plus": four individuals over age three, and one infant (2 and under).
One great alternative is the new Finding Nemo Family Suite section of
Disney's Art of Animation Resort. This incredible room has multiple sleeping areas -- including a master bedroom with its own separate bathroom!
If you have your heart set on Riverside, many of the rooms there do offer a trundle bed option. The almost-twin-size bed rolls under one of the larger beds in the room, and will certainly be more forgiving than the Pack-N-Play.
When you're ready to book, give the reservation line at call at (407) W-DISNEY, and let the magic begin!
See you later, celebrator,
-Deborah B.