Finally, after planning for almost 4 years, we made it to Munnar. One thing that I searched for before this trip was a description about the route (fast and best). Though I found the information in bits and pieces, it was not a holistic one. This is one of the major contributing factor for me to write about it.
Best option to get to Munnar would be to take a train till Coimbatore and hit the road from there on. There are 2 trains from Bangalore to Coimbatore. Planning in advance will be required to secure a confirmed berth in the train.