It is a standard size pack-n-play. We had one in a corner at WL in a room with 2 queen beds; a second one would have been a squeeze. I would ask for a king room for the floor space but then you lose the bath tub. I have not had a bunk bed room but that may also give more floor space: place pack-n-plays end to end up along the bunks. One thing we loved about the pack-n-play ... just throw all the loose animals, blankets, toys etc. into them when leaving the room.
Disney does offer bed rails if you want to avoid the pack n play ....
Another tip: ask for a step stool so the tykes can reach the sink or climb up on the bed.
At bedtime, we were really wishing for a second room/suite. We turned off all the lights and sat in the dark until DGSs were asleep then we turned on a low light and low volume on TV ...