I just have a few minutes, but wanted to point out some places to check out.
Near the top of this board, there is a thread called the disABILITIES FAQs thread ( you can also follow the link in my signature to get there).
Post one of that thread is an index that tells what information you will find in which post. Here are some I want to point out that should be helpful to you:
Post 11: Basic accessibility lists for each park. Includes Mobility Access entrances from WDW Disabilities park maps, attractions requiring a transfer from wheelchair or
ECV.
All attractions except Swiss Familiy Robinson Treehouse, Tomorrowland Transit Authority (Peoplemover) and Tom Sawyer's Island are wheelchair accessible to the point of boarding. Peter Pan is listed as "must be ambulatory", but can be ridden by someone who can walk a short distance.
Some attractions do not have lines that are ECV accessible, but will have a wheelchair that you can transfer to on request.
Post 18: MK attractions and
ECVs. Lists which have a difficult step on and which have a wheelchair car
Post 19: Epcot attractions and ECVs. Lists which have a difficult step on and which have a wheelchair car
Post 20: Disney Hollywood Studios and ECVs. Lists which may be difficult to board and which have a wheelchair car
Post 21: Animal Kingdom and ECVs. Lists which may be difficult to board and which have a wheelchair car
Post 22: Attractions where guests must stand unless they have mobility device
For those that involve sending, you would want to consider bringing the wheelchair/ECV into the attraction with you, even if you are parking it for other attractions.
Post 30: Travel to WDW with oxygen
There is no official WDW list of attractions where oxygen is/is not allowed, but this list was made from information from people ho traveled to WDW with oxygen.