I'm planning to go on a winter trip to Darjeeling. Will leave at ~4 pm from Kolkata and reach the hotel the following day at ~1 pm. The route will be -> Kolkata -> Mogra -> Nabadwip -> Krishnanagar -> Farakka -> Siliguri -> Mirik -> Darjeeling. 

Will chill in Darjeeling and do some local sightseeing for three days. 

Finally, start in the early morning from Darjeeling, and come back to Kolkata the same day.