Also keep in mind, buses during the morning and evening commute can be PACKED. If you absolutely need to travel during these times then do so, but I would try and avoid them. Even as a random tourist I would do so (packed buses will get you where you need to go, but they aren't the most pleasant experience in the world), but with a wheelchair it may be very difficult to get people to move out of the wheelchair area because there may just be nowhere for them to go.