Are there wheelchairs available for rent or to borrow if you can't walk a long distance?

no, but the place isn't very big

No

Didn't see not a one but its kind of accessible. The path is very gravel filled

I didn't see any when we went. The entire boneyard is dirt/sand. it's also not as big as you think. They do have an area you can walk back to if you want to sit and rest but if they are doing tour after tour they won't let you fall too far behind or walk through again by yourself.

I don't believe so.