Hi you can 1st day landing in goa and check in,1st North goa, 2ndSouth goa, 3rd dudsagar falls ,4 local area viewing, forth day you can fly back..
mess for any itenery plan...for goa , kerala, Andaman, ooty and kodaikanal.. pls reffer my travel chennai wings-8778954695
If you want to enjoy and explore Goa properly then you should spend atleast 7 days but if you have less days then you can manage the trip in 4 days as well. Do let me know if you want a customised itinerary according to your interest and I will help you plan one.