Went to Taman Negara about a year and a half ago for 5 days. Had a wonderful time. It was through Eureka Travel (Holland Village)Travelled up to Jerantut by night train but down side was that we arrived early hours of the morning. We were then picked up from the station and taken to Kuala Tembeling where the boat left at about 9am to Taman Negara Resort. Journey took about 3hours but is very relaxing and peaceful. I believe the boat only departs a couple of times a day.
The resort is situated in Taman Negara Park on the banks of the Tahan River and was ideal for this type of holiday; basic, clean and comfortable. I fully recommend taking the time to vist the park; a little awkward to get to by train perhaps, but well worth the effort.
Tara