Darjeeling is one of the majestic place to travel and itself is a large north-eastern district and part of the state of West Bengal. It covers Darjeeling hill town as well as several other important places including Siliguri, Kurseong, Mirik. Darjeeling and Sikkim hill areas are laid out and where are the important tourist destinations relative to each other. This is vital to plan your trip itinerary that can involve visiting several places in this area. Otherwise you may end up making unnecessary travels or taking longer routes and waste precious time of your vacation.
Sikkim is located adjacent and north of Darjeeling, is a separate state all together. But due to proximity of the two hill areas, many tourists make a combined visit for few days. And it is quite easy to get to one place from the other. Various places of Darjeeling and Sikkim are well connected through a network of road routes. There are of course check posts at the border areas of Sikkim, but it hardly takes any time if you have the required Sikkim Permit. If you are making a combined trip of both Darjeeling and Sikkim, you can visit any place first and then move to the other one. However in order to minimize your travel time within this region (i.e. Darjeeling district and Sikkim) and avoid unnecessary time & money, you need to carefully understand the location of the places that you plan to visit in the hills and sequence your trip accordingly.
If you are combining or visiting Gangtok or Sikkim, go through this Route Map of Sikkim as well to see another pictorial map and understand the various routes & destinations in Sikkim and how they connect to Darjeeling, NJP and Bagdogra.