The journey from Khanna to Mangalore spans about 2500 km. The most practical way to travel is by train, usually involving a connection at Delhi or Mumbai. You will cross the entire length of India. Expect a travel time of approximately 45 to 50 hours.
Total Distance: 2500 km by road, 2100 km air distance.
This is a very long journey; plan accordingly.
October to March for pleasant weather.