[sgh]

Best take plane. 
Fly by Firefly to Subang.
Take off from Seletar. 
Very easy. Reach airport and walk to plane.

Msia very big it depend where you want to go and if that place is near to any airport. Your proposed approach will not work for everyone as everyone destination in Msia are different. Not everyone is going to the 3 big states/cities, Johor, KL, Penang. There exist others who got ppl or relatives stay in other states like Perlis, Kedah, Ipoh etc for e.g