I am planning to go Kerala on 5th july for a week, can any one suggest me a nice Itinerary.I know its monsoon time their but have to attend friends marriage as well so cant extend that

Well I can start my trip from kollum on 6th July and have my return tickets from cochin on 11th.My tentative Itinerary is:

1)leave kollam on 6th morning.(reach kumarakom/Aleppey backwater.)
2)reach munnar on 8th morning.
3)reach kochi airport on 11th morning.

Now my basic questions are:

1) Which Houseboat to choose?(my budget is moderate and I want to stay only for 1 night in houseboat)
2) From where should I pick houseboat and where to get down?
2) Is their any possibility to add “kodaikanal” and “The Champakulam Moolam Boat Race” into my plan.
3) Minimum time to explore Munnar?

Please tell me the feasibility of the itinerary.

Thanks in advance.