*There are 2 ports of entries between Malaysia & Indonesia. The blue dots & arrow is Penang, Malaysia to Medan, Indonesia whereas the red arrow is Melaka, Malaysia to Prapat, Indonesia.

Incidentally, Penang to Medan is the better route as reckoned by a lot of backpackers since you start your Indonesian tour from the north, then simply make your way down south.

*As for going from Indonesia to Malaysia, either route is O.K. 'coz you'll go in a circular itenerary in Malaysia in order to see it all & so, you'll end-up back where you started as seen in my Malaysian articles.

Hence, either Penang or Melaka is O.K. unless if you're Thailand-bound, then you take Penang. But if you're Singapore-bound, then you take Melaka.