Your best bet is to stop by Guest Services and ask for the Guidebook for Guests with Disabilities. It will help you to know how to approach each attraction. You can always ask a CM at the entrances but they're often not easy to find. It's been about a year since I was there, but I remember waiting in a HUGE accessible queue line for Pirates which was outside the exit. They make sure that you wait at least as long as all other Guests. They did have the area roped off so you knew what it was for. I waited in a long line for IASW and then found I couldn't ride because they wanted to separate me from my service dog- not by much but in her mind she wasn't able to do her job and indeed she couldn't have reached me if I'd have needed her help. Other than that we really had no problems. My very favorite thing was getting to ride the virtual submarine attraction. They have a small building you go in with seats and spaces for w/c's and
ecv's and you see the entire show just as if you are in the sub! They had the same for the castle experience. As was mentioned, DCA is all mainstreamed and very easy to navigate.