Darjeeling And Gangtok Sight Seeing Points

I had recently been on a trip to Kolkatta, Darjeeling and Gangtok. Here are some points to keep in mind if you visit these places.

There are no direct trains to Darjeeling from any of the major cities. Most of the trains from major cities such as Kolkatta go to New Jalpaiguri (NJP) and from here you can either catch a train or a taxi to Darjeeling. The train starts at 9.00 in the morning and reaches Darjeeling at around 17.00 in the evening. Taxis are faster and reach Darjeeling in about 4 hours.
NJP (and Silugiri located very close to NJP), Dajeeling and Gangtok are like a triangle each situated at a distance of 80-120 kms from one another. The fare for shared taxi from NJP to Darjeeling is Rs.150, from Darjeeling to Gangtok is Rs.120 and from Gangtok to NJP is Rs.150 (prices may vary).
It should be noted that taxis (especially shared) in-between these places do not ply after 4.00 PM. So if you are planning to start for one of these places, it is best to start by afternoon. Else you may find it difficult to find taxi.
The train from NJP to Darjeeling is pretty famous. As mentioned above, it starts in the morning and reaches the other place in the evening. As a reminder, if you are planning to go to Gangtok on the same day on which you have taken this train, then it may not be possible because as I have mentioned above, shared taxis generally do not ply after 4.00 PM.
The road drive from Darjeeling to Gangtok is fantastic and should not be missed.

Keeping all the above points in mind, if you plan to visit both these places, then this itinerary, in my opinion would be the best:

If you are coming from Kolkatta, take Darjeeling mail and you will reach NJP the next day morning at around 8.00
Take a cab from NJP to Gangtok. You will reach Gangtok by afternoon 12.30-13.00.
Spend as many days as you want in Gangtok. But when going to Darjeeling, take a shared taxi. This way you will not miss the fantastic road trip from Gangtok to Darjeeling.
Spend as many days as you want in Darjeeling. Now when you are planning to go back, take the train from Darjeeling to NJP which starts in the morning from Darjeeling and reaches NJP by evening.
The same day evening you can book a train from NJP to Kolkatta and you will reach Kolkatta early next day morning.

Following this itinerary helps you enjoy both the road drive and the train ride with proper rest.

Lastly, I am attaching some sight seeing spots in Darjeeling and Gangtok just in case anyone of you are interested in visiting these places.