Kushalnagar to Somwarpet road. The route is curvy and not so smooth like the road till Kushalnagar from Mysore
This is the same route one would take to drive from Bangalore to Mangalore via Hassan. You'll drive on the 4 lane toll highway till a small town called Channarayapatna, that appears about 40km before Hassan.
Reach Tumkur Road (NH4) from wherever your starting point is in Bangalore. At Nelamangala, leave NH4 and get to the NH48 towards Mangalore. From Nelamangala to Channarayapatna, you'll be on NH48 for about 120km. You can cover this in less than 2 hours.
After that the driving is relatively slow phased, thanks to the 2 lane curvy route....
From Channarayapatna and Hassan there are a few left diversions towards towns in Coorg. These diversions and state highways, nothing compared to the 4 lane NH48 you've been on so far. Nevertheless, some routes have better roads than the other. One of the popular diversion is from Channrayapatna to Madikeri via Holenarsipur and Arkalgud.
Drive ins on the NH48: Try Mayura after Bellur Cross.
Swathi Delicacy (www.swathidelicacy.com) is great vegetarian drive in restaurant near Yediyur on NH48.
There is a Kamath Upchar outlet after Channarayapatna. The catch is, this is 10km after Channarayapatna on NH48. So its a 10km+10km detour back to Channarayapatna where the H.Narsipur diversion is. There is also a Cafe Coffee Day(CCD) also next to Kamath's inside the IOC Fuel Station.
Bangalore to Coorg by NH48 ( distance 291km ) route goes like this: Bangalore City –30km–>Nelamangala–44km–>Kunigal–46km–>Bellur Cross (Nelligere)–45km–> Channarayapatna –22km–>Holenarsipur–22km–>Arkalgud–22km–>Sanivarasante–20km–>Somwarpet–40km–>Madikeri Town
Coorg Route option 1:
Bangalore to Coorg via Mysore :
The Bangalore to Mysore route (SH17) : Bangalore - Bidadi - Ramanagaram - Chennapatna - Maddur - Mandya - Srirangapatna - Mysore.
Mysore to Coorg (SH88) : Mysore - Yelwal - Hunsur - Kempalapura - Piriyapatna - Bylakuppe - Kushalnagara - Suntikoppa - Madikeri .
Coorg Route option 2:
Bangalore to Coorg by NH48 ( distance 291km ) route goes like this: Bangalore City --30km-->Nelamangala--44km-->Kunigal--46km-->Bellur Cross (Nelligere)--45km--> Channarayapatna --22km-->Holenarsipur--22km-->Arkalgud--22km-->Sanivarasante--20km-->Somwarpet--40km-->Madikeri Town