U can go to kerla....but must have to plan ur days ...in 7 days u can visit 3 places like bekal..munnar amd alleppy.buy at every place you have to spend atleast 2 days to explore it fully.thare are lots of option even in karnatka that you can plan day wise and as per your return journey..like
1.gokarna 2.murudeshwar
3.bekal
4.munnar
6.alleppy.
7.kollam
they all are in sequence ..you can plan all of them aur some of them as per your starting and end journey..at that time natural beauty of these places is on peak
Come over to Kerala. You could plan wisely and have a great trip. The mixture of lands are the unique thing to Kerala. Upon your interest you could plan your days visiting hill stations, Beaches, Forests, Back waters, Cultural centres and many more. Planning the trip centering Kochi would be easy for you. You could visit Idukki, Alappuzha, Ernakulam and Thrissur districts which are nearer and are well connected with almost every means of transportation.