Click on the link below for map.
Marathahalli -- Hoskote
The route is as follows (around 42 kms):
Marathahalli -- Forum Value Mall -- Hope Farm -- Right onto Channasandra Main Road -- Take left at T-Junction towards Hoskote -- Left on NH 207 -- Left towards Kannamangala/Kadugodi from NH207 after toll gate, from the side of flyover -- Kadugodi -- Hope Farm and back.
While coming back, you may take right just after Kadugodi flyover, and you will come on ITPL road. Cross ITPL. Either take left at Big Bazaar (diagonally opposite to Prestige Shantiniketan), or left from further down at Hoodi junction. Cross Graphite junction, then right at Kundanhalli junction, and you have reached from where you started :) Zero displacement, but lots of fun, lots of calories burnt ;)
If you are interested in little off-roading, take left towards DPS on Hoskote Road. Its a mud road, but ok to cycle with scenic views. Keep going straight, and at the T-junction, take right. You will come out near Whitefield Railway Station.
Some good eateries in this area are Udupi Cafe (after Kannamangala, towards Kadugodi), Shri Ganesh Darshan (opp. Sai Baba Ashram, next to Kadugodi flyover) and Udupi Cafe (Channasandra main road).
Its good to have a rear view mirror on cycle, especially on right side. Makes biking much safer and comfortable.