The Moonrocks area is about 1 hour north of Reno - there is an organized DRN ride there every February. It is excellent desert riding there - vast area with a huge variety of trails and terrain. If you search the Reno Ride forums you can probably find directions in some of the old threads. Basically, take Pyramid Highway north to Winnemucca Ranch Road and look to your left for the Moon Rocks.
The Rubicon trail is fun! Well worth a ride before the snow comes and close to you. Extremely scenic in parts. btw, it is west of Tahoe, not east.
People that have invested effort in hand-building excellent single track woods trails (maybe on private land) are going to be reluctant to broadcast the locations of their 'members only' trails.
High Sierra is a club in AMA D-36; you can get contact info for clubs at the d-36 page,
www.ama-d36.org D-36 has some races in your area, too.
MRANN also handles races at riding areas in northern Nevada - you can google them and find their website.