The ADA guidelines for wheelchairs lists a "common wheelchair" as 48 inches long, so your wheelchair may or may not fit. Some ride cars can hold a little bigger chair, others can't.
This is the list of attractions where guests can stay in their wheelchair or
ECV for the attraction from the WDW Guidebook for Guests with disABILITIES (there is a link to it in the disABILITIES FAQs thread). I
bolded the things that are rides.
MK
Ariel's Grotto - character meet and greet
Castle Forecourt Stage (whatever the show is; you drive up an find a spot)
Country Bear Jamboree - audioanimatronic theater show
Donald's Boat - a kid's play area
Fairytale Garden
Frontierland® Shooting Arcade
Galaxy Palace Theater (seasonal)
Judge's Tent - character meet and greet
Jungle Cruise - there is a specific wheelchair boat which should have no problem accomidating a long wheelchair
Liberty Square Riverboat - this will not be a problem, you drive right on and the length of the wheelchair won't matter
Mickey's PhilharMagic - theater show; wheelchair length won't be a problem
Mickey's Country House - a 'house' you can drive thru
Minnie's Country House - a 'house' you can drive thru
Toontown Hall of Fame
"The Enchanted Tiki Room Under New Management" - an audioanimatronic theater show; length of the wheelchair won't be a problem
The Hall of Presidents - - an audioanimatronic theater show; length of the wheelchair won't be a problem
Tomorrowland Arcade - a game area; some of the games might not be reachable
Walt Disney's Carousel of Progress (seasonal) - - an audioanimatronic theater show; length of the wheelchair won't be a problem
It's a Small World - a boat ride. There are specific wheelchair accessible boats. The length of the wheelchair should not be a problem if it can turn fairly sharply
Aladdin - a ride, some longer wheelchairs won't fit
Buzz Lightyear and Winnie the Pooh are both rides with wheelchair cars. Some longer wheelchairs may not fit. You could try asking the CM at the entrance whether a wheelchair 52 inches would fit.
Epcot®
Guests may enter and enjoy these attractions in a wheelchair or ECV:
Mexico: Art of Mexico Gallery - art display
Japan: Bijutsu-kan Gallery - display
Wonders of Life: Cranium Command (seasonal) - an audioanimatronic theater show; length of the wheelchair won't be a problem
Wonders of Life: "Goofy about Health" (seasonal) - live theater, length of wheelchair won't be a problem
Wonders of Life: "The Making of Me" (seasonal) - movie, length of wheelchair won't be a problem
China: "Dragon: Ruler of Wind and Waves" Gallery - art gallery
China: "Reflections of China" - a 360 movie (all around you), wheelchair not a problem. If you park near the back you will have the best view
Imagination: "Honey, I Shrunk the Audience" - 3D movie with wheelchair spots in the theater
Imagination: Journey Into Your Imagination with Figment - ride; some longer wheelchairs won't fit. If your wheelchair fits on Buzz Lightyear and Winnie the Pooh, it will probably fit
France: "Impressions de France" - a movie with wheelchair spots in the theater
Innoventions East & West - displays of new products
Canada: O Canada! - a 360 degree movie, wheelchair not a problem
Norway: Stave Church Gallery - a little hard to get into, but not bad
The American Adventure: The America Gardens Theatre - wheelchair not a problem; a choral group sings in the rotunda of the building
The American Adventure: The American Adventure - an audioanimatronic show with specific spots for wheelchairs
The Land: The Circle of Life - a movie with specific spots for wheelchairs
The Seas with Nemo & Friends: All Attractions - there is a new attraction there which is a ride with a wheelchair accessible ride car. It is similar to the car in Imagination
Morocco: "Treasure of Morocco" - a display
Universe of Energy: "Ellen's Energy Adventure" - some longer wheelchairs may not fit in the wheelchair space
Mexico: El Rio del Tiempo in Mexico - a boat ride. There are specific wheelchair accessible boats. The length of the wheelchair should not be a problem if it can turn fairly sharply
The Land: Living with the Land - a boat ride. There are specific wheelchair accessible boats. The length of the wheelchair should not be a problem if it can turn fairly sharply
Disney-MGM Studios
ABC Sound Studio - show with wheelchair spots
"Beauty and the Beast" at the Theater of the Stars - Broadway type theater show with spots for wheelchairs
Disney-MGM Studios Backlot Tour - a tram ride; wheelchair length should not be a problem if you can turn to get into the tram
Fantasmic! - a theater type evening show with specific wheelchair spots
"Honey, I Shrunk the Kids" Movie Set Adventure - a play area; some areas are too narrow for wheelchairs
Indiana Jones Epic Stunt Spectacular - theater show with specific spots for wheelchairs
Muppet*Vision 3D - 3D show with specific wheelchair spots
Lights, Motors, Action! Extreme Stunt Show - outdoor theater show with specific spots for wheelchairs
Playhouse Disney - Live On Stage!
The American Film Institute Showcase - a display, wheelchair not a problem
Voyage of the Little Mermaid - a theater show, wheelchair length not a problem
Walt Disney: One Man's Dream - a display, wheelchair not a problem
The Great Movie Ride - some wheelchairs may be too long. One DIS poster with a longer wheelchair said she had to ride sideways. We have found this car to be kind of a tight fit for DD's wheelchair (about 48 inches long), but were able to turn it to ride facing forward.
The Magic of Disney Animation - portions are a movie and other portions are displays. One portion is an interactive part with desks for guests to draw at. The wheelchair length should not be a problem.
Disney's Animal Kingdom® Theme Park
Caravan Stage: "Flights of Wonder" - a live bird show, with wheelchair spots
Cretaceous Trail - accessible trail
Conservation Station - accessible displays
Discovery Island Trails -accessible trails
Grandmother Willow's Grove: "Pocahontas and Her Forest Friends" - a live animal show with wheelchair spots
It's Tough To Be A Bug - a 3D movie with wheelchair spots
Lion King Theater: "Festival of the Lion King" - a live show with wheelchair spots
Maharajah Jungle Trek - accessible trails
Pangani Forest Exploration Trail - accessible trails
The Boneyard - a play area
TriceraTop Spin - a ride. Some longer wheelchairs will not fit
Wildlife Express - train
Affection section in Rafiki's Planet Watch - a petting zoo area
Kilimanjaro Safaris - a tram ride, somewhat bumpy. If your wheelchair fits on the Backstage tour at the Studio, it will fit on this tram.
TriceraTop Spin - if the wheelchair fits on Aladdin, it should fit.
As was already mentioned, there is a 'chicken exit' for each of the rides you would not be able to ride without transferring, so you should be able to do a preshow and leave before proceeding to the ride.
Soaring is a really easy transfer if you are able to transfer at all. You could watch the movie 'preshow', which does show the ride cars, proceed with the rest of the guests into the show area and if you decide you can't transfer, you can just continue to the exit.