Postscript: Some ViaRail Travel Advice

1. Pack light and accessible. Space on the train is tight and you don't want to give up any of that valuable sleeping space to a suitcase any more than what is absolutely necessary. 
2. Bring flip-flops for the shower.
3. If you have a lot of electronics and have the money, get a room(ette.) Unlike berths, the rooms have an ac outlet so you don't have to be tethered to an ac outlet during the day while waiting for your ipad/camera/cell phone to charge. Or, if your berth is close enough to the washroom, bringing an extension cord is a valid option too. Oh, if you're going with the extension cord, bring some duct tape so people don't end up tripping over your cord. Another valid (but riskier) option is to simply plug in your device in one of the Park cars overnight. 
4. Go for the early meal seating. Whatever you do, do not go for the last meal seating because you'll end up eating dinner at 9pm. No matter how strong you think your stomach is, it still needs time to digest a three-course dinner, especially if you have the dessert.
5. Don't forget the (almost) daily time zone changes!
6. Once you board the train in T.O., drop off your stuff and head to the dome cars. That's where the free champagnes and snacks will be served.
7. Be ready for some internet detox.  Four days without internet except for the four-hour pitstop in Winnipeg.
8. Polish up your Scrabble skills. It's a great way to socialize with fellow travelers and just about the only game onboard.
9. Leave the rail guides at home. Read them before you travel and make some notes, but they were not particularly useful on my travels. The mile markers can be hard to see (if they're there at all) and you'll be too busy taking pictures to be following the guides.