The journey from Khanna to Coimbatore spans about 2600 km. The most practical way to travel is by train, usually involving a connection at Delhi. You will cross the entire length of India. Expect a travel time of approximately 48 to 52 hours.
Total Distance: 2600 km by road, 2200 km air distance.
This is a very long journey; plan accordingly.
October to March for pleasant weather.