From munnar Cochin is 4 hours away. There are buses from munnar where you take Kalady route reach angamaly then take a bus to Cochin. Another way is by cab. On the way you could stop at Cheeyappara falls and valara falls. Karadipara view point plus tea plantations look from the top is Mesmerising. Neriamangalam bridge ranikallu spot is famous.
The best way to travel from Kochi to Munnar would be to take a cab, a distance of 126.6 km approximately & takes around 3 hr 32 min via NH 85!! Places to explore between Kochi & Munnar:
Kodanad/Kaprikad Elephant Camp
Thattekkad Bird Sanctuary
Wonder Valley, Adventure & Amusement Park
Anachal Jeep Safaris Happy journey 🙌