[hvkumar]

2 choices:

Route 1: Take NH47 via Kollam, Alapuzha, Kochi, Trissur, Palakkad, Coimbatore, Avinashi till Bhavani. At Bhavani, turn off NH47 and go via Mettur to join NH7 at Toppur. From Toppur, follow NH7 via Dharmapuri, Krishnagiri and Hosur. Distance around 750 kms, doable in a day. Problem is witth your schedule - starting from Trivandrum at noon means you will get clobbered by day traffic till Trissur. Ideally, leave early in the morning (4 am). If that is not possible, better to leave in the evening after 7 pm and drive through tthe night.

Route 2: Go on NH47 till Kochi, then switch over to NH17 via Kodungallur, Chavakad, Kunnamkulam, Edapal till Kozhikode. Switch over to Wayand Road and go via Kalpetta, Sultan's Battery, Gundulpet and Mysore to Bangalore. Same problem with start time. Keep in mind if you take this route, expect wildlife on road between Kalpetta and Gundulpet in night and early morning.