Forgot to mention tipping:

Cabin attendent: $5 or $10 at the end of the trip, depending on the service.

Dining car server: At a regular (sit-down) restaurant, most Americans will tip 15-18% of the bill. Since your meals are included with your room, go with $1 at breakfast and lunch, and $2 at dinner. (By the way: at "fast food" restaurants where you carry your food to the table, like McDonalds, tipping is not done at all.)

Lounge car attendent (which really means snack car attendent): anywhere from nothing to $1, depending on what you are buying. He'll have a tip jar on his counter; I usually just give him some of my change (a lot of people don't tip this guy at all -- he does deserve something).