If you stay in 檳城 for 5 days, you may not need to be hurry.
I would suggest you to join a local tour to Langkawi for one day.
Then, you may go to
(1) Beach and swim for 1 day
(2) Peak for half day
(3) Butterfly farm for half day
(4) Enjoy lots of food and drink for the rest of the day.
So if you choose Penang, do not expect too excited activities, it is a place to relax and enjoy food only.