Pack some nice homemade food, cause this isn't a short trip !
There are direct flights, trains and buses for this journey. Hyderabad (Andhra Pradesh) to Cochin (Kerala) distance is 1117 km and you can get there by flight in just over 1 hour and 30 minutes or by train fares starting from ₹ 471.
The heat there will make you sweat, but it's surely bearable.