Oh where to start. The whole place is a maze of trails that probably started as deer tracks, but have since formed into trails.
You really need a guide to find places like the Monkey trail etc, and will will be happy to show you. Myself and some of the mtbbritain.co.uk lot are meeting on the 7th May in the evening if you wanted to join us.
If not, if you do the dog until the begining of S13 then go over the road and through Tackeroo caravan site to the car park opposite the entrance and continue through that there is a nice flowing descent that leads to the quarry. You have to follow the track from the car park to the fireroad and the trail starts right in front of you.
Otherwise there are loads of the special events area too, but describing how the get there will be a nightmare,
There are also some cheeky ones withing the follow the dog too.