I've taken the CA Zephyr to Reno & back a couple of times. It's a nice trip, the seats on the train are comfy, like you said there's a dining car and a lounge / observation car on the train, and the scenery over the mountain pass is lovely.

But you don't want to be in a hurry to reach your destination! The last time we went out there, the train was delayed for over an hour somewhere near Sacramento. Another time heading home, the train was about 4 hours late coming into Reno from SLC.

But that said, I think it would be fun to take the train out to SLC.

- Jo.