I can't really say much about Peter Pan because it's not a ride I'm "allowed" to ride. The ride cannot be stopped or slowed down and the limited space for boarding isn't enough for me to make the transfer onto the ride.
It's a Small World has the problem that most rides in Fantasyland have. It was designed long before wheelchair access was thought of. So the line leading down on the entrance isn't wide enough to accomodate wheelchairs/ECVs. Currently wheelchairs/ECVs wait in line until the line starts downhill and then they are diverted to the exit. I believe this is also done because the wheelchair/
ECV needs to be at the exit, imagine trying to get a wheelchair/ECV across the boat to the other side. I know that my wait for It's a Small World are usually as long and often longer then the people who go down the normal line. I have to wiat for the wheelcahir accessible boat to cycle around and sometimes there is a waiting line for that boat. As for those walking on with "no wait" that sounds lie a CM problem and they should have staggered those loadings.
Jungle Cruise is an odd one. I've always gotten Fastpasses for it and then when it was time to board I go to the wheelchair line. I do know the standby and fastpass lines are not designed to allow a wheelchair to travel through the lines so they send the wheelchair/ECV users to a different line. Again on this other line I wait for the one boat that has the wheelchair lift. Sometimes there are a couple people in front of me also waiting and I wait through as many cycles as necessary to baord. I've also been turned away from the ride because the lift boat was out of service.
One thing I'd like to comment on is the number of people accompaninga wheelchair/ECV. Officially it should be no more then 6 total in the party, the wheelchair user and 5 others. If there are more then that the CM should have split up the party.
E.T.A I think you guys have picked 3 of the 7 1/2 rides in all of WDW where the wheelchair user may bypass the line. Obviously that doesn't come close to "get prefered access to everything" or "giving preferred access to all rides and most events".