Recently a trip to Ottawa took us to Fun Haven Indoor Amusement Park. It was our son’s birthday and he wanted to do something fun with BOTH his parents.
Fun Haven is a perfect place for all ages and we found it very accessible. It was spacious and the only area Shawn was unable to access was the Escape Room upstairs. They also have party rooms and even though they are mostly upstairs they have one on the ground floor. There is several accessible washrooms and even a companion washroom.
Fun Haven has an arcade, indoor roller coaster, mini bowling, laser tag, bumper cars and escape rooms. Shawn was able to participate in laser tag and had a great time. There is a second floor with steep ramps in the laser tag area. It would be fine for a power chair but a bit difficult for a manual chair.
Fun Haven does offer discount rates for attendants but you would need to call ahead to confirm.
Great place for the whole family. 
Accessible Getaways 