Are there multiple levels/steps or stairs, elevators?

I actually pushed my mother in a wheelchair on our visit. All of the gardens and exhibit centers are handicap accessible and very easy to maneuver. The trails and hiking areas are just that, trails in wooded areas with dirt paths.

There are steps to access different gardens and elevators in the buildings

Yes there exist elevators

Yes

There is all of those things

The designers of this Garden had it right. Access won't be an issue anywhere you go.

There are stairs, but where there are stairs there are ramps/elevators