From the southern tip of Malaysia to the northern tip of Malaysia is about 8-9 hours driving (not too bad). from east to west, 2-3 hours to the central and the due to underdevelopment in the west of Peninsular malaysia, it takes another 5-6 hours.However, it will be way longers to travel in the Borneo side of Malaysia, may takes days from one tip to the other end. Not that small actually.
One of the smallest country is Singapore.................. a tiny tiny island south of peninsular Malaysia. Round trip of Singapore is only 4-5 hours I think