DAY1: Arrive at NJP/Bagdogra. Transfer to Darjeeling via Mirik by taxi (this is a longer but scenic route. Takes about 4.5 hours. Pre-paid taxis take shorter route. So you will need to pay a bit extra to the driver or take a separate taxi. You will see Mirik lake and lovely tea gardens on the way). However this is possible if you reach NJP/Bagdogra in the first half. Otherwise take the usual route (3.5 hours). Night stay in Darjeeling.
DAY2: Take 3-point tour early in the morning to watch sunrise over Mt. Kanchenjunga from Tiger Hill, followed by visit to Ghoom Monastery and famous Batasia Loop. Don't miss out on the Samosas (singaras) sold by the locals at Batasia. Come back and take your breakfast in the hotel. Later visit the Chowrasta Mall. Sit on a bench and Relax here for a while, then complete a round along Mall Road. Walk up the Observatory Hill to Mahakal Temple from the Mall road and soak in the views and wonderful ambience. In the afternoon, go for the 2-hour Toy Train Joy Ride. But book the tickets in advance. In the evening, take a stroll along Nehru Road through many shops and Bhutia stalls... do some shopping. Try to take your dinner at the famous Glenary's Restaurant. Overnight Stay in Darjeeling.
DAY3: Take breakfast at Keventer's on the open roof terrace. You can get the famous full English breakfast here if you want. Then take a sightseeing tour of Darjeeling- go for either 7-point or mix point tour. The main attractions to cover are Happy Valley Tea Estate, HMI & Zoo, Tibetan Self Help Refugee Center, Tenzing Rock, Ropeway (cable car), Rock Garden etc. Overnight Stay in Darjeeling.
DAY4: Check out in the morning (by 8am), take a taxi from the stand and move to Gangtok (takes about 4 hours). Check into the hotel, freshen up and walk down to MG Marg, the hub of Gangtok - Smoke & vehicle free boulevard square with shops and restaurants lined up on both sides. A great place to sit on a bench and feel the carnival like ambience. Walk down to a restaurant, take a relaxed lunch. Post lunch, do some shopping. Also walk down to nearby Lal Bazaar for more shops. Remaining day at leisure. Overnight at Gangtok.
DAY5: Go for a full day 10-point sightseeing tour (see Gangtok sightseeing tours).
DAY6: This is the day to check out and transfer back to NJP/Bagdogra. If you have time in the first half, then take a taxi and visit some unseen attractions like the Himalayan Zoo - you will see many rare and endangered species of Himalayan animals like Red Panda, Snow Leopard, Tibetan Wolf, and lot more that are kept in natural habitats. It's a large zoological park in forested area. You will need some 1.5 to 2 hours for the visit.
7 days/6 nights Darjeeling & Gangtok itinerary
Follow the same itinerary above from Day1 to Day5.
DAY6: Make a full day trip to Tsomgo Lake - a glacial lake at an altitude of 12,400ft and followed by visit to the much fabled Baba Mandir. You can also combine Nathula Pass. Visit Gangtok sightseeing tours and see the section under 'Day trip from Gangtok' for details and permit requirements.
DAY7: Transfer back to NJP/Bagdogra.