Upvote:2
Having visited Malaysia a few times, here are things in my bucket list that you can try out; they are all easily serviced in 5 days thanks to great transportation infrastructure in Malaysia.
To start off with, as you are in Penang, there is plenty to do there from shopping to beaches and then there is the botanical gardens as well.
You can take a ferry to Langkawi which has great beaches an epic sky bridge above the forest.
Other destinations:
Genting Highlands. This is a resort near KL (1/1.5 hours by car), or take a cable car and is way up in the mountains (5,710 ft). Great if you are into casinos. Try sipping a latte at the Starbucks with clouds literally at your feet.
Cameron Highlands. You can find great large vasts of tea plantations and great nature trails here. You did not say when you were going to be in Malaysia, so if you decide to go to Cameron Highlands make sure you check the weather first and what trails are available. If you are into nature photography this is also a great option.