How tough is the hiking through the cave? My Mom can walk and get around pretty good but she does have an oxygen small carry purse and can only do short distances at a time.

The guides were also good at letting you go at your own pace and waiting for those who were slower.

The humidity is always at 99% in the cavern, so that maybe a challenge. The walkway does have several relatively steep inclines and declines too, and stretches a little bit less than a mile, and then there is the walk back to the start of the caves too. It's not a jungle gym though, so no climbing rocks or anything like that.

It can be a bit strenuous as you walk in a decline and incline. There are not really any steps that I recall but there is a handrail through most of the cave. The guides do allow you to somewhat walk slower if needed. I stayed at the very back of the group and took my time walking through. I dont have experience with oxygen use but in sure You can ask the guides too. You make various stops and there are benches to sit down as you make your way through. Good luck!