I'm glad I found this; I might have an upcoming trip with my wife and her parents (2 rooms), and we're not sure yet if her dad will be coming too or just her mom.
From the discussion of the open sleeper ticket above, I wonder if it'd be simpler to just book it for both of them and then cancel his if he decides not to join us?
Also, FWIW, the base fare for a room on the CZ (EMY-CHI) appears to be $48 higher than value fare but less than the flexible fare - saver = $141, value = $176, flex = $339, and roomette = $1052 for one / $1276 for two.
On the Coast Starlight (LAX-EMY), the fare basis appears to be a business class seat - saver = $54, value = $68, flex = $130, business = $86, and roomette = $202 for one / $288 for two.
I think one of you guys responded on my Amtrak Unlimited thread, assuming it's the same @
zephyr17.