read about what its like using an ECV in DL. if i remember properly, you have to park it outside rides like the ones in fantastyland, and then they bring you in the exit. with my manual chair, i pull right in, but there is usually not enough room for an ECV. and it is different for DL and DCA...
I just remember that there is a difference for an ECV and a manual chair. you will need your crutches with you in the park to get on and off things... I have never done DL in an ECV, but i am sure others here have good advice...