What used to be a fantastic place for kids, was the first bum central for Las Vegas. Once Lied moved out, all the security devices moved in. It used to be cozy, now it is claustrophobic.
Do not go near the periodicals. The smell isn't for the faint of heart. This is where the indigents hang out. Not much anyone can do about it.
No longer a viable space for kids. Go to the Children's Discovery Museum instead. Not much to say, like a lot of the parks in Vegas, the "public" has taken over and ruined it. That's Vegas for you. Your best bet is the outlying area libraries.