Not really that much to do there. It's really all about the food. After about a week, you'll probably just find yourself doing the same things and going to the same places every day.Why ?
One of my ex girlfriends was of Malaysian background and had extended family over in Penang. Went there 3 times and whilst it was fine because we had the advantage of spending time with people and take us places, (mostly places to eat), there isn't really much else to do.
Also, my ex and I noticed each time we went back that Penang was getting noticeably dirtier.
A week would be long enough