From Pasadena, take the 210 freeway to the 15 all the way to Vegas. My best recommendation for a tourist spot is the Calico "ghost town" outside of Barstow. This is the little town that the Knott family purchased most of the buildings that are in the ghost town area of Knotts Berry Farm. Calico is a mix of old and new buildings but there is a Western shoot-out show and interesting things such as a bottle house.
Or if you want to shop, the Ontario Mills mall is a good stop; and the mall at Stateline has some good shops also.