wm1207,
Thanks, you're welcome.
There are no direct public transport to both 2 places from Penang Island. For Air Hitam Dalam, I first crossed the Strait of Malacca to Butterworth by ferry from George Town as I was staying on the island. Then I took a taxi to go there and asked the taxi driver to pick me up at the end of the day; I paid RM 30 for the 30-min single trip after negotiation. As most of the taxi drivers were not familiar with the place, a clear route map was necessary to show to the taxi driver.
For Sungai Sedim which is about 1.5 hrs drive from George Town, I hired a local bird guide for 1/2 day. He picked me up from the hotel I stayed early in the morning and sent me back after the trip.
Paul