The Disney Gallery has an elevator for guests with disabilities (or those that can't handle the stairs). I'm trying to remember but I don't think there was an obstruction on the floor at entryway to the balcony, so a wheelchair ought to be able to get there fine.
Although I'm guessing it would be a little more comfortable if they were able to leave the wheelchair in the gallery itself and then sit in a chair on the balcony.
Although I'm guessing it would be a little more comfortable if they were able to leave the wheelchair in the gallery itself and then sit in a chair on the balcony.