Hello All, quick heads-up.
I completed the Bangalore-Kodai trip in my Innova Crysta with senior citizen parents and kids driving along with me quite comfortably, with very timely and perfect snack and bio breaks, using some great suggestions from Haldian and Rajeevraj - Thanks a ton to you guys!
Here is a short summary of stop-over points, for reference of everyone else taking this route in future, and these worked perfectly for my family and me.
Here goes:
Stop-1: Roughly 1.5 hours from Whitefield, Bangalore.
https://goo.gl/maps/2shdjr455z3Qsk8P9
Adyar Ananda Bhavan - A2B
NH 44,Dharmapuri-Bengaluru Road Gundalapalli Village Shoolagiri, Chinnar, Tamil Nadu 636807
Stop-2: Roughly 2 hours from previous point.
https://goo.gl/maps/4ycnCx8YXprHMv8w6
GRAND ESTANCIA
349/3 Bangalore, Bypass Rd, Narasothipatti, Salem, Tamil Nadu 636004
Stop-3: Roughly 2.5 hours from previous point.
https://goo.gl/maps/8qn7RnwFxzFsPztNA
Adyar Ananda Bhavan - A2B
Thomaiyar Puram, Adiyanuthu, Tamil Nadu 624002
Stop-4 (optional, we skipped it): Roughly 40 mins from previous point.
https://goo.gl/maps/1D94QpHQUvSbqpmb7
Hotel Temple City
NH 45, Chennai - Theni Hwy, Genguvarpatti, Tamil Nadu 624203
I decided to skip the last one and head straight to my Kodai location (Xanadu Birkenhead) and that took me exactly 2.5 hours from Stop-3, amongst lashing rains and thunderstorms all along the ghat roads!!
Hope this helps~