Yeah, park at Brandon Country Park rather than High Lodge. To ride the waymarked trails, go out to the main road and cross straight over. Turn almost immediately right (20 yds) and follow the trail down. It splits several times, but as long as you keep heading in roughly the same direction they all spit you out in the same place.
This is at the bottom if the Beast. You'll see a sign for one of the waymarked trails on the left, which will take you back to High Lodge in a couple of miles.
The red and black have now both been called reds. If you head down to the start of the trails, the old black goes straight on and the red turns right. Neither of them are really red though but good fun.
If you stay on the Brandon side there are loads of trails, but they can be hard to find if you don't know where you are going.
Someone might be able to give you a GPS file of this weekend's D2D course, which will have some good bits on it.