[hvkumar]

Onward journey, go straight down on NH7 to Bangalore, and continue via Hosur, Krishnagiri, Dharampuri, Toppur, Mettur, Bhavani, Coimbatore and palakkad to Cochin. Day 1 could be to halt at Bangalore.
Detailed route: Hyderabad-Kurnool-Gooty-Anantapur-Penukonda-Bagepalli-Chickballapur-Bangalore-Hosur-Krishnagiri-Dharmapuri-Toppur-Mettur-Bhavani-Avinashi-Coimbatore-Palakkad-Trissur-Cochin

Return could be via Coimbatore, Ooty, Mysore. And from there to Bangalore and same route back to Hyderabad.
Detailed route: Cochin-Trissur-Palakkad-Coimbatore-Mettupalayam-Conoor-Ooty-Kalhatti-Masinagudi-Mudumalai-Bandipur-Gundulpet-Nanjangud-Mysore-Bangalore-Hyderabad


Currently, roads are bad in Coimbatore-Cochin stretch, but you can expect that to be repaired by the time you are on the road.

In case you fancy, you can take off from Dharmapuri and visit Hogenakal Falls which is 50 + 50 kms off the route, and will mean a 4-hour detour (including a 2-hour halt).

On the return, you can drive straight to Ooty from Cochin, hop to Mysore. You can drive direct to Hyderabad from Mysore without halting at Bangalore. If you take the Outer Ring Road from Kengeri you can bypass BangaloreCity and go via Dasarahalli to NH7 (Hyderabad road).

Roads in Ooty area are bad - perpetually for last 1-2 years, regardless of the season. Road from Ooty to Mysore is good via Masinagudi.