The train is a bit different. Since you're on it for a longer period of time and you're not hurtling through the air at 30,000 feet, there's a different set of considerations. Here are some useful train travel tips:
Food: Amtrak offers a dining car on its longer routes with a diverse, but pricey menu. However, if you want to save some money, you're welcome to bring your own food onboard. I prefer less-perishable fruits and vegetables, jerky, granola, summer sausage, and some cheese.
Drinks: You can also buy a variety of beverages on the train or bring your own. Their single caveat is that you drink their alcohol in their Dining, Lounge, or Cafe Cars. If you bring your own, you should have paid for a Sleeper Car in which to drink it. If they catch you with it in a "public area", I imagine they will dispose of it and watch you closely.
Toiletries: Sitting for so many hours at a time without access to a proper shower can leave you feeling pretty scuzzy. Bring along your shaving kit (if you're not one of the bearded) to freshen up halfway through. You'll feel better just realizing that you can have your safety razor within reach.
One essential item that improves my mood when I've been on the fireline for days is a pouch of facial wipes. I prefer Simple wipes. They're alcohol-free with no perfumes and dyes. They also don't leave you smelling like a baby wipe.
Bedding: Bring a neck pillow and stowable blanket. The Coach seats are larger than an airplanes and recline pretty far. If you're willing to spend some extra money, sleeper cars are available.
Entertainment: Bring a few books you've been meaning to read. You have the time. DVDs or downloaded movies and a laptop or DVD player can break up the trip. Noise-reducing headphones are key on the train. Also, look out the window. The cross-country routes offer some spectacular views.
Sleep Aids: For some, the rhythm of the train can be soothing. I'm a light sleeper so I'll be using an herbal supplement, night mask, and ear plugs. Valerian root is a natural, mellow sleep aid that can be found in health food stores and some of the larger stores. Melatonin is another popular choice. With a little research, you can find something helpful with few adverse side effects.
Baggage: Each passenger is allowed two carry-ons, each less than 50 pounds. That's right. You can bring 100 pounds of your stuff onboard without paying a dime. If you don't want your baggage with you, you can stow two pieces at no charge.