Wow! Have you taken shorter train trips? If not, I ***strongly*** recommend that you do this to make sure you enjoy riding on a train. Some are better than others, I'm sure, but try to choose a similar type of train.
Personally, this is something I would never do because I hate riding on trains. My brother loved trains until he travelled from the Midwest to the West Coast by train. Never again.
One thing to remember on trains is that food and drinks are ***very*** expensive. Most people would want to carry a lot of their own food with them.