Northeast India is connected but not always convenient — flights land in Guwahati, Dibrugarh, Imphal and a handful of other hubs, but the last mile is often a shared jeep or a long mountain drive.
Inner Line Permits are required for Arunachal Pradesh, Nagaland and Mizoram if you're not a resident — apply at least two weeks ahead. Shared Sumo jeeps are the backbone of inter-town travel across the hills, leaving early morning from designated stands.