The only times I have ever been able to get assistance with an ECV (disassemby and loading; unloading and assembly) has been at the deluxe resorts where there is valet parking. At the parks, at Downtown Disney, and at the non-deluxe resorts I have been on my own. Once in a great while someone passing by has volunteered to assist.
If you are staying on property, just about all of the Disney Transportation is ECV accessible.