I'm from Malaysia, lived there all my life and came to college here.
Good places to ride to include Cameron Highlands, Fraser's Hill, the remote side of Penang Island, the coastal roads between Penang and Lumut. Road bike parts might be a problem. Try and stick to mountain parts... the local bike stores are not as well stocked as bike stores here. There might be a good bike store in some major towns but you'll have to do some research there. I'm from there and I don;t know, but then again, i picked up cycling in the US.
Get a cellphone. The prepaid services are very cheap and you can just use them and dump them. Take a GSM phone there and just buy the card. The phones are expensive in Malaysia. Maxis has the best coverage and you can SMS back to the US.
I know there is a guy named David who helps folks out a lot. http://www.bicycletouringmalaysia.com/
On the West coast, you can find many English speaking folks so communication is not a problem. East coast, it might be an issue in the rural areas. Be sure to check out thing that might offend Islam as Malaysia is largely Muslim.
What else? let me know if you need a contact in Malaysia, I have friends and family that would love to help while you are there.