The California Zephyr still has a full service dining car, below is the current menu. (Click on Menu to Enlarge)
I have a strong interest in Amtrak because my wife and her family are from Ouray, Colorado. I have ridden on the Amtrak from Dearborn, Michigan to Grand Junction, Colorado over twenty times. The train leaves Dearborn at about 7 AM and arrives the next day at Grand Junction at about 4 PM. When we get there we have a rental car waiting for us, if the train is late the rental company will wait for the train.
Coming back we do run into issues, missing our connection to Dearborn at Chicago. When that happens they put us on about five buses and they load them according to the final destination. We board the AnnArbor / Dearborn / Detroit and Pontiac Bus.
We always ride in a coach seat, it is only one night on the train. We have three children travel with us and they love riding the train. We pack food for them and ourselves but my wife and I will dine in the diner car.