Having spent 7 years here in Vegas, I highly recommend 'Oasis RV Resort' at 2711 Windmill Lane, Las Vegas.
***YES, it's a bit more than a KOA, etc: BUT well worth the coin.
Very secure, guarded front gate: nice pull through lots.
Only about 11 minutes off the strip: easy access in/out.
Try it, you'll like it.....