I really love the long distance journey by train, because, it gives ample opportunity to sleep, without any tension. You can order your foods, and the guys from pantry will come and wake you up to give the food. And everything comes in time, from morning tea/coffee, breakfast, lunch, evening snacks / tea / coffee , dinner. So you got everything at your place. And the cell phone most of the time is out of network, so not much calls. That helps to sleep nicely.
In India, always book a 2 AC berth, because otherwise, its a pain traveling in other classes, as there will be lot of littering by several small vendors, and there is also possibility of theft and intrusion. These guys do not enter the 2AC or 1st class however, so life is smooth in those compartments. The only exception being, if you have a small kid near you who cries a lot ( Experienced once :), felt like I should get down and go by another train)