[red cuillen]

You could do it, but wouldn't do either of them justice. It would be a drive thro the Joshua Tree Park, and an up the tramway, quick look at the view, and back down again. Would help if you based yourself at one end to get an early start. We did Yucca Valley then drove south, but even then we spent over 4 hours along the route. Once on top of Mt Jacinto there is a lovely walking trail to follow with spectacular view points over the valley. So much cooler on top too!
Both attractions can be busy, especially on weekends so could be a slow drive thro the park and you may be best booking a time for the tramway. Stayed in Palm Desert the following night, plenty to do in the area, some ideas here if you didn't get to view my report hot springs/joshua tree/ tramway pics