Most but not all of it is.
The central areas, including the Visitors Center and pond area, are ADA accessible, and you can drive to other areas that are accessible.
Some areas are some areas are not wheelchair friendly. The Auto tour and paved paths are plenty to explore though!
I would say overall it isn't too wheelchair friendly, but the driving tour is nice. You can pull off at a few places and relax though.
There are a lot of hills, but yes its good for wheel chairs. They have a paved walk way that might be easier for a wheel chair
There are car paths and part of the Japanese garden is paved, but lots of hills. Best to stick to the auto tour for now.
My 90 yo mother in law walked most of the paved pathways. You should be fine
The grounds have sidewalks so it should be fine.
Thanks! Your answer is awaiting moderation.