The journey from Gangtok to Visakhapatnam covers roughly 1500 km. You must first reach NJP or Bagdogra. From NJP, you can take a direct train to Visakhapatnam Junction. Flights from Bagdogra to Visakhapatnam usually connect through Kolkata or Hyderabad.
Total Distance: 1500 km by road, 1200 km air distance.
Ensure you book a train that stops at Visakhapatnam Junction.
Kolkata is the most convenient hub for this connection.
October to March for pleasant weather.