We like the Harrah's Laughlin Hotel/Casino, Laughlin being about 20 miles north of I-40 when you cross the AZ-CA border. Great buffet, nice pool, Colorado River access, and they have a large game room for the kids while the adults are in the casinos. The hotel prices in Laughlin are usually quite reasonable compared to Vegas for instance, so even if you don't gamble it's a good place for an overnight stay.