For any ride line that can't accommodate an
ECV (Pirates, for example), a temporary loaner wheelchair is available. You can park the ECV in stroller parking.
Guests using wheelchairs,
ECVs or other mobility devices don't need
DAS in most cases. The CM can see the mobility device and direct you where to go. But, at WDW, most lines are accessible, so you would just use the regular line (or Fastpass Plus line if you used one of your Fastpass Plus for that attraction).
At WDW, all attractions except Tomorrowland Transit Authority, Swiss Family Robinson Treehouse, the attractions on Tom Sawyer Island are wheelchair and/or ECV accessible up to the boarding area; they are marked on park maps and signs at attractions with a wheelchair symbol or a stick figure getting out of a wheelchair.
The park maps (and signs in front of attractions) have an icon that shows if the line is ECV accessible or not. If the little stick figure is getting up from the ECV, it's not ECV accessible.
Before you park the ECV, let the CM at the ride entrance know that you will need to borrow an attraction wheelchair to use in line. They will direct you where to park and provide a wheelchair for you.
For WDW, there are only a few attractions that are not wheelchair accessible in the regular line and have separate accessible entrances. These are the ones that give a wheelchair return time card.
If it's not busy, they will not issue a wheelchair return card, but will let you right in to the accessible line. If you are using a Fastpass Plus, you should also be allowed right into line without getting a wheelchair return card.