Kerala is one of the most beautiful places on earth. I have just been back from a trip covering Munnar, Thekkaddy, Cochin, Trivandrum and Kovalam.
Munnar is a good place to stay. The climate is very good and remains moderate at all times. But, if you are interested in seeing places rather than just sit and relax, I suggest that just a single or max 2 days at Munnar is sufficient.
Thekkady is a wonderful place, once should stay there for atleast 3-4 days. And do not miss the massage center there. Thekkady is the best place to get yourself a good massage, especially for people whose jobs are just to sit (like Software Engineers). After the massage you can easily feel the difference. I would like to warn you, although there are MANY massage parlours out there, be sure you go to one that is authentic. There are some places that are very commercial. Luckily I knew a person there, and he took me to one, where generally the local keralites get their massage. And the person also had a degree in Ayurvedic medicine.
The best part of the trip was the 24 hour ride in the traditional HOUSE BOAT. It was just too good. The services were excellent, and imagine having dinner in the middle of the lake looking up at the stars and then trying your hand at fishing! And the house boat takes you through the legendary Kerala backwaters. It is just too good, one should not miss it. And do not forget to eat BLACK FISH, since it is found only in the kerala in these back waters.
The other place we went to, was Kovalam. The Kovalam beach, I rate as one of the best and neatly maintained. You can check into any resort at Kovalam, which will be facing the beach. unfortunately we could stay there only for 1 day. I recommend a person staying there atleast for 3-4 days. There are lot of this you can enjoy there. And when you are at this place, try having a Candle Lit dinner on the beach. One side will be the Arabian Sea, the other side will be Palm Groves, and on top the Full Moon with glittering stars. It is remains as the most memorable dinners for me. And try eating LOBSTER for dinner.
A trip to Kerala can be the most enjoyable one. The people are very good, and realize the importance of tourists. I did not face any problem anywhere. And the food is great. I was told before leaving by many people that the food will not be good. But if you are a Non-vegeterian do not miss eating fish at each place you have lunch or dinner. Keralites know how to cook fish really well.