Based on the recommendation of my friend Rob who began using this service, over Labor Day Weekend, I traveled to Palm Springs via Amtrak for only $24 each way.
We ride an Amtrak train between Los Angeles Union Station and Fullerton Station and then catch an Amtrak thruway bus between Fullerton and Palm Springs. There are several destination stops in the Coachella Valley for this Amtrak bus, such as downtown Palm Springs, Palm Springs International Airport, Indio, etc.
The train car was clean, comfortable and had WiFi. But guess what? So did the Amtrak thruway bus!
Note: SunLine Transit Agency, which provides local transit service within Palm Springs and the Coachella Valley, has begun a new Commuter Bus between Palm Desert and the Riverside Metrolink Station: Line 220, covered by the Palm Desert Patch. It will be interesting to see how it does.