Landscapes on the way to Munnar from Kochi are very beautiful as you can see in the pictures below. Total distance by road from Kochi to Munnar is 130KM and will take you approximately 3-4 Hours. You can go by bus or can hire a private taxi. Munnar is called Kashmir of south India. Munnar is laced with western ghat hills and it is a very romantic place in India. Places to be visited en-route from Kochi to Munnar:
Both are majestic(see pictures below).
4)Kodanad for Elephant ride (but best is do elephant ride at Thekkady spice gardens)