Hi Amy,
Your trip will be here before you know it! I'm so sorry to hear about your husband's foot issue but not to worry, Disney is a great place to visit for guests who require many types of assistance.
A limited number of ECVs are available for rent on a same-day first-come, first served basis at all four of the theme parks as well as Downtown Disney. Please note that ECVs are not available for rent at the water parks. Advanced reservations are not accepted so I'd suggest arriving early to ensure availability.
ECVs may only be used in the theme park where they are rented. ECVs can be held if you leave a park and plan to return to the same park on the same day - just make sure you inform a Cast Member at the rental location when you return the ECV. If you park hop to another park, you should retain your receipt from the first park you visited to obtain an ECV at the next park at no additional charge. Keep in mind that ECVs may not be available at the second park as quantities are limited.
Check the link on the Guests with Disabilities section on the WDW website for
Guests with Mobility Disabilities. There you'll find a list of the attractions which allow Guests in ECVs to remain in them, ones that require Guests in ECVs to transfer to a wheelchair (they will have some courtesy ones on hand for this) & which attractions require Guests to transfer from ECV & wheelchairs to board.
Wishing you many magical memories :-) Allison