Hey auzzi. I fly out on 30th Nov unfortunately. Im not sure about the fares for trains exactly, but my lonely planet says 19RM from KL to Butterworth and then 11RM Butterworth to the Thai border. Thats 3rd class, triple price for 1st class. Divide by 2.8 for AUD price.
My rough itinerary is KL, a few islands - pangkor, penang, langkawi, KL, singapore and hopefully the jungle if weather good.