Hi Todd,
Oh no!! I hate to hear that your little Princess broke her foot! Be sure to let the Characters sign her cast! Yes, you can rent a wheelchair at each of the four theme parks, the two water parks and Downtown Disney Area. It is $12.00 USD per day for wheelchairs at Theme Parks and $12.00 USD per day plus a $100.00 USD refundable security deposit for wheelchairs at the Downtown Disney Area.
If you would like to rent a wheelchair for multiple days, Disney Theme Parks offer a length of stay rental ticket where you make a one-time payment transaction for as many days of rental as you will need. Wheelchairs are available for $10.00 USD per day when rented for multiple days. Upon visiting a Disney Theme Park, show your receipt at the wheelchair rental location and you will be expedited through the queue with a reduced wait time. The length of stay rental option is not available or valid at Downtown Disney.
A limited number of wheelchairs are available at each Disney Resort Hotel. Contact Guest Services or the Front Desk for assistance. A $315 USD deposit will be held on the Guest room account—charged only if the wheelchair is not returned. Unfortunately, you will not be able to "reserve" a wheelchair prior to arriving at Disney.
Have a magical day!
Ca'Sandra
P.S. Be sure to have the Characters sign your little Princess's cast!!!