My wife's doing a half marathon there on Saturday. I thought I'd take a bike along and have a ride round for 2 hours whilst she's pounding the fire roads.
This is the route for the half marathon;
Map of the singletrack (pdf, sorry) is here;
I've got three questions;
1) Will the runners make doing, say, the red trail impossible.
2) are the trails reasonably well signposted or is it more a question of riding around trying to find interesting bits?
3) I assume it's all doable on a rigid singlespeed as the weather for the rest of the week doesn't look great and it's the only bike I've got with mud tyres?
 I think the dotted blue line on the race route may be the red cycle trail? looks like I'll be mostly ok if it is then?