I have been there recently and found it very accessible There are ramps to each floor rather than stairs and it is in a circular way that looks over lake and rock faces. I saw a bear from one spot!
There was a young Mom with her daughter in wheelchair who lives locally who has a membership because it is so accessible and her daughter loves to come there. The theatres are great for getting in and out and the one layered theatre has a ground floor entrance.
There is also an elevator and the washrooms each have dedicated stall and toilet has bars and toilet has a back.