I like the lower level better than the upper level because very view people are walking by your roomette. Number 13 is a good one, my wife in I were in #12 the last time and I didn't like it that much. Some folks on the upper level think they have to take there suitcases up and down the stair way 5 times a day. I can't figure out why they can't put there stuff in a small carryon or a backpack and leave there stuff in the room. Our big luggage is in the baggage car.
Numbers 11, 13 & 14 are great rooms also. The nice thing about the lower level also is there are 3 restrooms on the lower level and a nice size shower. Lots of folks who have the bigger rooms on the upper level, use the lower level shower. In there expensive room, they have a shower, sink and toilet, trouble is to take a shower you have to set on the toilet, sort of sh*t, shower and shave LOL. Oh, best time to take a shower is when the train slows down for a stop, best time is a smoke break stop, they are around 5 minutes or even when they change crews, little more time to take a shower.
If you have a iPad, be sure to take it. Put your iPad on the window to take the best pictures or videos. Oh and be sure to take along a power strip, there is only one outlet in the room, so with a power strip you can run or charge many items at once.
You picked a good trip to go on, the California Zephyr is a great trip!! Have your camera or iPad ready at all times. Have a Great Trip!