Are you doing the Meteor or Star? The reason I ask is that under the normal schedule:
-Southbound, you'll get dinner and breakfast on both (and probably lunch on the Meteor).
-Northbound, you'll get dinner, breakfast, and lunch on the Star; on the Meteor, you may get lunch; you'll get dinner, and breakfast is a maybe (the train is often early post-WAS, and the diner doesn't usually open up until you get out of WAS). On the Variable Star (i.e. the tweaked schedule over the next few weeks), you'll get dinner and breakfast.
All of this assumes an on-time train, of course. Given the choice, I'd say do the roomette SB if you're on the Meteor or Variable Star coming home (assuming that you can crash when you get home); if you're on the regular Star, it's more of a toss-up IMHO.