You could try asking this question on the DisAbilities forum, since they have a lot more expertise in this area.
If you have the "stroller as wheelchair" GAC then you will not have to take the child out of the stroller until you reach your table, if she is too big to carry easily. They will then park the stroller for you or show you where to park it until you need it at the end of the meal. I say this since I use a wheelchair at Disney and always transfer to a chair for my meals and this has been the procedure for us. Can't imagine why it would be different for a "stroller as wheelchair".