Joshua Tree National Park comprises regions of two deserts: the Colorado (the hot dry eastern portion of the park) and the Mojave Desert (the high cool western portion).
You can drive to Keys View at 5,185 feet above sea level and see out over the Coachella Valley to Palm Springs and the Salton Sea.
Actually Joshua Trees are succulents, related to the Yucca bush. According to the Michelin Green Guide to California , these were named by Mormon travelers. The strange contorted branches made them think of Joshua pointing the way to the promised land.
and when you're not too lazy to drag out the 4x5 view camera... (click on the thumbnail below for an experience in sharpness)
... of Joshua Trees
OK; maybe I could only find two.
If you keep driving east on California Highway 62, you will cross the Mojave Desert into Nevada.
Visit in March or April so that you can enjoy the wildflowers. Take water and food into the park. Allow at least two days to see most of the interesting road-accessible sights. Bring a hat.
Stay and have dinner at the 29 Palms Inn in the town of Twentynine Palms: (760) 367-3505. The inn is less than a mile from the park entrance.
If you're a camera nerd, here is your checklist for Joshua Tree: