I recently went there myself and I realized for myself what I had to do there so that my trip was magnificent:
1. Get a Dose of Naga Culture at the Hornbill Festival
2. Observe Local Life at the Kohima Night Market
3. Trek to Japfu Peak
4. Feast on Authentic Naga Delicacies
5. Live in Tribal Huts
6. Tour the Naga Villages
Day 1. Arrival in Imphal and bit of sightseeing. Day 2. Full day sightseeing in Imphal: Japanese war memorial, INA war museum Loktak Lake etc. Day 3. Travel to Kohima. You can visit the famous war cemetery here. Day 4. Head to Khonoma Village and spend a relaxing time strolling around and interacting with the locals and way of life and return. Days 5 and 6. Head to Dzukou Valley for a wonderful trekking experience. Day 7. Travel to Dimapur for your return journey home. Hope this helps :)
Yes. Nagaland will be best explored if you have a minimum of 5 to 6 days in hand. Also there are a lot of scenic spots in Nagaland so don't forget to miss them out. The most preferable option for you would be to reach Kohima from Dimapur and then head to the adjacent sight seeing places. While in Kohima you can visit the very famous war cemetery for a soft touch of history. For the other places, you can explore you can pay a visit to Dzuleki which has some beautiful landscapes that are totally worth your time. From Dzuleki head to Khonoma that's Asia's first Green village and deserves a visit. People here are exceptionally sweet and are ready to offer help at any point. If you have an eye for history, Khonoma is a perfect spot for you. Simoma Fort would quench your thirst for that. Also don't forget to visit the handlooms for you can see quite an exceptional amount of intricacy that goes into making of a traditional Angami shawl. From Khonoma, you can head to Dzoku Valley for some thrilling adventure. Dzoku Valley is a nature's treat to trekking lovers. The trek is moderate but is an uphill walk in the beginning. Make sure you don't carry much luggage as the route is very slippery. Also wear proper shoes with a decent grip. Once you reach the top, you shall be welcomed to breath taking views of the valley down below. It is advisable that you stay overnight here in the valley. There is a government arrangement (basically a hut with a large room) for a night hault and you can have a proper amount of rest. Tips-
1. Nagaland is often laden with rains for almost a major part of the year so make sure you carry a raincoat or ponchu along with you everytime. 2. Most of the places in Nagaland like Khonoma run on tourism. The entire economy of the village depends on the amount earned from the tourists like you and me. So while visiting these places, move with a travel company at all times. 3. Since Dzuleki and Khonoma are a little off the grid, there are only homestays and limited number of guesthouses available in the region. You might not find the luxuries of a five-star hotel but the people over here shall leave no stone unturned to make your stay a memorable one. Hope this helps!