Most of the queue's are "mainstreamed", where a wheelchair or
ECV can go through the regular line until the actual boarding area. At that point you park right at Load and when you get off, it is there waiting for you. If Load and Unload are in different locations, the chair or ECV will magically appear at Unload.
If the queue is not mainstreamed, you will be directed (either at the start or partway through the queue) to go to the alternate entrance.
There are a few attractions where you do have to switch from an ECV to a wheelchair; you leave the ECV there and pick it back up on return.
Many restaurants you can park an ECV in the lobby or right outside the entrance. And parking in a stroller parking area is always acceptable.