Hey the route suggested by Shynish is perfect IMO. I have been to Guruvayoor , Munnar and Thekkady before and these are places worth visiting. But you said only 5 days , is it possible for you to cover the tour suggested by Shynish?
But be prepared for poor road condition in Kerela , sorry fellow mallus no offence meant. And also beware of the Kerela state transport buses , they drive like they own the road!