Welcome to disABILITIES
First of all, are you talking about a "power chair" or an "electric convenience vehicle" (which is usually referred to as a
scooter or
ECV)? A power chair is generally for a person who has very little mobility, while an ECV is generally for a person who has difficulty with prolonged walking or standing. A power chair is generally customized for the individual and uses a joy stick for control, while an ECV is more generic with a tiller for steering and a lever of some sort to control speed. Normally the rental companies will only rent you a power chair if yoiu have one and can provide the customization information.
ECVs can be rented in the Disney parks for $30 per day, plus a $10 refundable key deposit. They are available on a first-come, first-served basis. If you change parks midday you have to turn in the ECV and show the receipt at the second park to only pay the key deposit. However, often the parks will be out of ECVs after early morning.
Off-site rentals ae generally better ECVs (three wheels instead of four), cost less for longer terms (such as $30 per day but only $199 for a week and the price drops for longer rentals), and are available to you at all times.
Here are the urls and phone numbers of the off-site locations used by people on this board. Note that most of them will rent power chairs and regular wheelchairs, as well as ECVs.:
Walker Mobility:
888-726-6837
www.walkermobility.com
Care Medical:
http://www.caremedicalequipment.com/
407-856-2273, Toll Free U.S and Canada (800) 741-2282
Randy'S Mobility is in Kissimmee
http://randysmobility.com
407-892-4777
Colonial Medical
http://www.colonialmed.com/about_cms.html
800-747-0246
ScootAround
http://www.scootaround.com
Toll-free, US and Canada 888-441-7575
I have used Walker a few times. They will ask for a credit card and charge it the day before arrival. They will deliver the ECV to your hotel bell services before your arrival and pick it up there after your departure. Their rates, especially for longer than a week, are much better than Disney's. Also, their scooters are much better.
You don't say if you are renting a car or what. If you are using a car for getting around, the ECVs break down into five pieces, the heaviest about 39 pounds. They take about a minute or so to take apart and about two minutes (once you are used to it) to put it together.
If you are not using a car, you will find that the Disney transportation system is generally rated very good to excellent for transporting disabled people.
I am not familiar with rental policies at the non-Disney theme parks. Of course, if you rent from an off-site company you will have the ECV available at any park you go into.