There is not much walking required.
You have to walk from the check in point to the truck. I don't know if they'd allow you to take an
ECV to that point or not. It would be accessible if they would. From there you have a ramp to go up, which is a series of switch backs. Not too long at all, with handrails you can easily lean on and can take all the time you need to get up.
Once up at the top there is a bench to sit on if you need a break from standing. Other than that, you would walk from end to end of the enclosure, depending on the movement of the elephants.
Other than that, I'll just say I don't agree with Josh. I guess I'm just more easily entertained than he is. I can watch the animals doing absolutely nothing for hours.