We just got back from POR this past Sunday. We were in Alligator Bayou building 35. They do sleep 5. We only have a family of 4, and didn't request a trundle bed, but it was there so we used it. My boys (5 & 9) don't sleep well together so it was a blessing for us! My only comment about the room was it has VERY LITTLE privacy. The bathroom is TINY and not usable for changing clothes in. The sink area opens up directly into the room, making it impossible to get ready in the morning and not wake others who are still sleeping. As for space, I think if you moved around the table and chairs a bit, you'd get your stroller in there ok. There isn't much drawer space in the armoire, but we never un-pack our suitcases so it didn't much matter for us.
While we LOVED the resort itself (it is beautiful!), Fort Wilderness cabins are a much better fit for our family. We are planning our next trip for 12/05. My mom will be with us on that trip, so we'll either get two value rooms, or we'll stay in a cabin. Do some research on the cabin...they are WONDERFUL!!!! Plus you'd have the bonus of a full kitchen.
Good luck planning!!