@SN
Wonderful SN. Probably, if you are not coming by car I may think that you are crazy, simply because I am crazy
If you want to take a fast drive to Chennai, take Madurai>Trichy>Villupuram>Chennai route - 765 kms
If you want to avoid going to Chennai and directly come to HH I will suggest this route,
you will enjoy your drive with the beauty of nature - then take Punalur>Pathanamthitta>Kanjirapally>Mundakayam>Peerumede (KKRoad).Karadykuzhy>Kumily (Thekkady)>Kambam>Theni>Dindigul>Salem>Krishnagiri (consider staying here)>Kuppam>Palamaner>Madanapalle>Horseley Hills - 840 kms.