NEW EDIT: I've actually mapped the one continuous loop of the new trail (Directly below). Park in the upper lot near the baseball fields and cut down the bike path. You'll see a clearing as the paved path cuts left down a hill. Head through that clearing and keep an eye out for the MTB trailhead on the left.
NEW MAP IS DIRECTLY BELOW. THE WHITE DOT IS WHERE THE TRAILHEAD STARTS.
I'm not sure that this map will help you at all. But I would have liked it. The best thing to do it ride it. This was my third time out there riding these trails over and over again, and I'm just now getting a feel for what is where... and I think I've barely scratched the surface of the new stuff merging with the old stuff.
Diamondback that will be perfect for a first real mountain bike experience. Neil gave that thing all kinds of heck today. He even tried to ride through a tree at one point. The tree showed him who's boss, though.
Like I said before, this is a great new trail system if you want to ride in Lexington. And you don't need crazy skills. You could ride it slower and have a blast. You could mash the pedals, hit some fun jumps and have a blast. It's a great option.
Get out there.