Booking in advance

Hi,

I will be arriving in Delhi in early Janurary and leaving from Mumbai with three weeks inbetween. I have pencilled in going to Varanasi and Udaipur. How busy is it at that time of the year? I would prefer to do as little booking as possible to keep my trip flexible as possible.

I will most likely book my train trips in advance, is it expensive/difficult to cancel or transfer train tickets?

You need not book in advance for January. Then again, its easy to cancel reserved tickets; and the cancellation fee is paltry provided you cancel more than three days in advance of the date of journey.