Best places to visit in Kerala during July - September Months?

Hi, I'm a traveler myself but for past one month or so I've been busy with work and personal things that I couldn't go much around. My college mates are planning a week's trip and coming from Banguluru, Chennai and Pune. They never been to Kerala before and wanted to see Kerala and also get a quality time with the old friends gang. I was thinking which will be the best places to take them to? We will be travelling in four wheelers and I believe it won't be a matter to travel anywhere in Kerala. We will be starting from Kochi, I believe, as they will taking flight to COK. So, it would be great if there are any inputs. Thanks for your time.