Was up there exploring about 20 years ago. I thought they closed access to it, when they built the catch basin. There is the big cave with the fork in it. We went to the left, took about an hour+ to make our way around. Very neat, watch for snakes. Going past the old mill footings, there is another cave system that has collapsed downward. Be careful as it is fairly deep. You can see the old RR bed where they went up and doubled back on itself below the footings. The Track bed was once very visible, and you could trace it back to where it crossed HWY 160 just east of buffalo, and east across rainbow blvd. Rhodes Ranch and other development have obscured most of it, but there are a couple of spots where the track bed is still visible near taco bell near buffalo. There once was a surviving rock ravine support for a bridge in a big gully where Rhodes Ranch is now.
It sounds like a nice little jaunt, i hope you find some fellow explorers. I have prior obligations, and live off windmill so it would have been a easy drive west.
PS: new batteries are your friend
if you do decide to go in.