Aleppy is mostly backwater tourism. Plan to arrive early morning at Alappy or Kumarakom bota jetty. you can have shikara boat ( small boat for upto 4 people with the budget of 600 to 1000 for 2 to 4 hrs trip ) or whole house boat price starring from 6000 and above depending on the numbers of bedrooms, mezzanine, balcony etc . or Government boat service through the backwater. this will be very budget friendly.
after that you can go to Cochin and roam around fortkochi, or Lulu mall have dinner etc. stay in kochi or from kochi you can have 3 hours journey to munnar you can stay at munnar as well then enjoy munnar hill stations