Aside perhaps from Sikkim, that's not off the beaten track. If you haven't already bought Lonely Planet and Footprints guidebooks, do so, most of your questions will be answered.

For information on train travel in India, see seat61.com.

I don't know anything about hostels in India, but there is cheap lodging available. Stay on the river in Varanasi.

No trains anywhere in Sikkim.

We loved Sikkim. We were not impressed with Darjeeling - and it certainly isn't off the tourist track. If you are interested, click on my name and you'll see a list of my trip reports.

Bagdogra is the gateway to Sikkim via air. It's a good 4-5 hour drive from there to get to Gangtok. If you are coming by train, your gateway city is Siliguri. At Siliguri there is a taxi stand, you can buy a seat in a jeep going to Gangtok. The drive will be another half hour longer from Siliguri.

The weather is warm during the day in both eastern and western Sikkim, but cools off dramatically at night. Northern Sikkim is cold year around.

BTW, in Kolkata, I highly recommend at least cone day with Calcutta Walks. It will really give you a feel for the city.

Thank you both, Kathie and Thursdaysd for your suggestions! No matter how many Lonely Planets one reads, they never beat people's own experiences and stories.

Well, if you're looking for experiences, you might try my 2001 Indian train trip, including Kolkata, Darjeeling and Varanasi - http://wilhelmswords.com/asia2001/index.html - start at Into India. It's old, but I don't think things have changed too much, certainly not when it comes to the trains.