It hasn't been explained yet how attractions without MainstreM lines will work.
One rumor is that those attractions would use return time tickes, given out at the attraction to anyone with a mobility device/who needed to use an accessible queue.
Another rumor is that guests with
DAS cards will get a return time for those attractions, but guests without a DAS would get return time passes.
This is a list of non-Mainstream attractions at WDW. Many of them are shows and the wait for guests using the accessible line is no different than other guests
Most attractions for all parks are listed as "Enter through standard queue" for attractions without Fastpass or "Obtain a FASTPASS OR use Standby Queue" on the Guide for Guest with Disabilities maps for each park. There is also a large red box on the maps which says "Guests with any mobility or queue related assistance needs are encouraged to use the Disney's FASTPASS option where ever possible." There is the same explanation about how to use Fastpass as on the regular park maps.
These are the attractions in each park with a different method of access other than the regular line, as listed on the map:
MK
WDW Railroad:Enter using ramp on the RIGHT on Main Street
WDW Railroad:Enter using wheelchair ramp on RIGHT at Frontierland
Big Thunder Mountain Railroad: Obtain Fastpass or see Host for options. If FASTPASS is not available, enter thru access on RIGHT
Country Bear Jamboree:Enter thru door on LEFT
Hall of Presidents:Enter through door on RIGHT
Liberty Square Riverboat:Enter through exit on RIGHT or LEFT
it's a small world:Follow directional signs to designated load area
Peter Pan's Flight:Obtain FASTPASS or see host for options. If Fastpass is not available, see a host for options.
Prince Charming Regal Carrousel:Enter through exit on RIGHT
Dumbo:Enter using ramp on RIGHT
Tea Party:Enter through exit on RIGHT
Space Mountain:Obtain a FASTPASS or see a host for options. If FASTPASS not available, enter through queue on RIGHT
Epcot
Spaceship Earth:Enter through the exit on the RIGHT or LEFT
Gran Fiesta Tour Starring the 3 Caballeros:Enter through the Standard Queue. Follow directional signs to designated load area.
American Adventure:See a host or hostess for access to second floor
Impressions de France:Enter through LEFT side of entrance hallway
Studio
Great Movie Ride:Enter through the Standard queue. A host will provide directions in the pre-show area
Studio Backlot Tour:Enter through the standard queue and stay to the RIGHT
Fantasmic:Enter through the standard queue and stay to the RIGHT
Animal Kingdom
Wildlife Express Train

roceed through standard queue. A host will direct boarding
The Boneyard:Enter through the designated access gate