I visited Sinharaja in April 2005, the rainy season had just started and as expected, we experienced a fair amount of leeches. We approached Sinharaja from the Ratnapura end, I think there are several areas where one can enter, and this was the region closest to us from where we were staying in Avissawella.
It took around an hour and a half to get there by road on a holiday, just one day before the Sinhala / Tamil New Year. I'm not sure how long it will take to reach there with traffic on a normal day. We arrived there around 8:30am after leaving our base in Gettahetha, Avissawella at around 7am.
All of us were Sri Lankans and the rate we have to pay to enter was lower than what a foreigner would have to pay. We paid for our tickets and picked up our guide and headed towards the entrance in our hired vehicle. The road leading up to the entrance was rather bad and it took a bit of time to get there as we had to travel at a slow pace avoiding all the potholes.
Upon entering Sinharaja, we hiked about 1 and a half kilometers and climbed about 350 meters to reach a mountain summit from where we could see all the surrounding hills and valleys, it was really a remarkable sight. I took my video camera along and recorded every aspect of our journey. It took us around 2 hours to get there and another 2 hours to descend. We were all quite exhausted but the guide didn't seem to even break a sweat. There were many leeches that latched themselves onto our shoes and socks along the way, and if your alert and check yourself every now and then will notice them before they can bite you. I managed to dust off several on our way up and basically managed to get back unscathed right until the very end of our journey, where I slacked a little, didn't pay attention and finally noticed one on my socks drinking away, right through it.
Basically it cost me about Rs. 275 to get permission to video tape my experience. It will cost double for foreigners. The van we hired cost about Rs. 30 per km and with the call up charge (Rs. 650) we had to pay since we ordered it through a friend in Colombo it cost us a total of around Rs. 6,000. The entrance ticket price was very low, around Rs. 30 for locals. The guide cost around Rs. 400 and we gave him a tip of around Rs. 500 as we really enjoyed our experience. Getting a pair of leech socks is a must if you want to prevent leech bites. Tuck your jeans or trousers into these and you're ready to go.