I live in Vegas. When my friends come in town I take them here. ESPECIALLY if the weather is nice. The mall is all outside, there are a ton of restaurant options, there's regular parking and valet parking, they have all the smaller stores you'd want in a mall [no flagship stores- Google it for a listing of their stores].
They have a small train that drives around and carries the kiddies. And they have a little hut that makes warm chocolate chip cookies...need I say more.
It's about 2 miles south of Mandalay Bay on Las Vegas Blvd. There's also some late night venues here too if you don't feel like hitting a club. Sometimes on the weekends they'll have old car shows and art shows etc. It's great.