People drive REALLY fast around the Palm Springs area, so if you are going 80, be prepared to be passed by a lot of people going 90!
If you need to make a pit stop halfway, I recommend Blythe. There are gas stations and fast food restaurants, and it's about the only town with those things before you get closer to Palm Springs. There is also a park there with a playground, so if you have kids that need to stretch their legs and burn off energy, it's a good place to stop (although it's one of the dirtiest parks I've ever been to, and I would never use the bathroom there!).