There are a few attractions that have Wheelchair Entrances. When they have them, it is because the regular entrance is not wheelchair accessible, so a special accessible entrance is the only way in.
AK and the Studio were built with Mainstream Access, which means that the lines are wheelchair/
ECV accessible and people using wheelchairs or
ECVs use the same lines as everyone else.
This is a list of the Mainstream Attractions from the official Disney Website:
Mainstream Attractions
Magic Kingdom® Park
Ariel's Grotto
Astro Orbiter
Buzz Lightyear's Space Ranger Spin
Donald's Boat
Judge's Tent
Mickey's Country House
Mickey's PhilharMagic
Mike Fink Keelboats (seasonal)
Minnie's Country House
Pirates of the Caribbean
Space Mountain®
Splash Mountain®
Stitch's Great Escape!
The Barnstormer at Goofy's Wiseacres Farm
"The Enchanted Tiki Room Under New Management"
The Hall of Presidents
The Magic Carpets of Aladdin
The Many Adventures of Winnie the Pooh
The Timekeeper (seasonal)
Tomorrowland® Indy Speedway
Toontown Hall of Fame
Walt Disney's Carousel of Progress (seasonal)
Epcot®
FUTURE WORLD
Imagination!: All Attractions
Innoventions East
Innoventions West
Mission: SPACE
Test Track
The Living Seas: All Attractions
The Land: Soarin', Lion King movie
Universe of Energy: "Ellen's Energy Adventure"
Wonders of Life: All Attractions (seasonal)
WORLD SHOWCASE
China: "Reflections of China"
France: "Impressions de France"
FriendShip Boats
Norway: Maelstrom
The American Adventure: "The American Adventure"
Disney-MGM Studios
Disney-MGM Studios Backlot Tour
Fantasmic!
Lights, Motors, Action! Extreme Stunt Show
Muppet*Vision 3D
Playhouse Disney - Live On Stage!
Rock 'n' Roller Coaster® Starring Aerosmith
Sounds Dangerous - Starring Drew Carey
Star Tours
The Great Movie Ride
The Magic of Disney Animation
"The Twilight Zone Tower of Terror"
*Voyage of the Little Mermaid
Walt Disney: One Man's Dream
Who Wants To Be A Millionaire - Play It!
Disney's Animal Kingdom® Theme Park
Caravan Stage: "Flights of Wonder"
DINOSAUR
Grandmother Willow's Grove: "Pocahontas and Her forest friends"
It's Tough To Be A Bug
Kali River Rapids
Kilimanjaro Safaris
Lion King Theater: "Festival of the Lion King"
Maharajah Jungle Trek
Primeval Whirl
Theater in the Wild: "Tarzan Rocks!"
The Boneyard
TriceraTop Spin
The shows (even the one with Mainstream lines) have a limited number of wheelchair/ECV spots inside the theater. Once those are filled, no one else using a wheelchair or ECV can be let inside (even if there are seats for people not using wheelchairs). We have come to Voyage of the Little Mermaid to use our Fastpass and been told that all the wheelchair spots for that particular show are already filled, so we will have to wait for the next show (even though they were letting in people from the standby line).
Many of the wheelchair entrances are accessed after waiting in line for a while (Haunted Mansion is an example); the wheelchair entrance to that is just a little before the 'regular' line reaches the turnstiles to get into the building.
Once inside a show area using a wheelchair entrance, like Spaceship Earth, Haunted Mansion, Kilimonjari Safari, we are not boarded immediately. Because of fire safety and evacuation rules, each attraction has a limit on the number of people with special needs/disabilities that are allowed in/on at a time. We may have to wait quite a while until they have room for us. Some attractions, like the Safari, have a wheelchair ride vehicle. We have waited 40 minutes at the Safari, while people who could walk in were getting on trams as fast as they could walk and some trams were even going out partially filled because people were not getting there fast enough.
I'd invite anyone who thinks it's easy to travel with an ECV or wheelchair and that users of them get all sorts of 'perks' to try one for a day. There are lots of people who post on the DIS Boards that their mind was changed after they had a temporary injury and needed to use one for a few days.