If you come down to the Grand Prix meet at Fish Creek West this Wednesday you'll get a shiny map of the area ;)
Neat area that's for sure. Is there a lot of single track trail there down there (i.e. unofficial MTB trails?). I was cruising on some but they weren't long in length. Always met up with the bigger main trails in the end.
I still haven't run on a lot of the park so I can't say how good they are for MTB but there are many little trails marked on the map. They are pretty much all short (there are so many bigger tracks in the way) and a lot end in the middle of nowhere according to the map. It looks like if you started in the west of the park you could go a fair way east on the south side of the creek staying on single track.