All from a quite frankly superb exodus trip cycling through Kerala, a holiday I'd happily repeat and bettered only by a couple of months in New Zealand South Island IMHO:
Exodus Kerala trip
Totally agree with Singlespeedpunk. Disinfectant handgel from Boots, use continiously, rehydration just in case, and worth going to a local chemist as soon as you arrive and stocking up on anti-biotics
Cycle up to Ooty hillstation (1600 mt climb) frollowed by dramatic descent, dropping 2200m through the hills and tea-covered slopes of the Western Ghats to the Indian Ocean. Its about a 40 mile descent!
Aruvedic hostel near Alleppey
Two day houseboat trip in backwaters well recommended (carry a decent bottle of white in your luggage to make the emost of the Sunset experience).
Explore the town of Cochin
The coast between Cochin and Kovalum
Avoid Kovalum - I thought it a bit of a dump compared to the rest of the coast although some of the beachside hotels are Ok for a couple of nights!