There are normally higher winds here than at the Marshall launch which is about 300m (1000') lower.
Marshall is an unusually reliable site, especially in the summer. Beginning May 1 there are often 100 soarable days in a row. How high you get and how far you might go XC depend on your skill but also largely on the day's conditions. Southern California often has a temperature inversion that limits soaring to 300-600 meters over Marshall launch, but some days are much higher.
Non-CSS-members have to sign a waiver and pay a daily fee of 10USD! USHPA membership required!
> see: http://www.crestlinesoaring.org/siteProtocols
Access
There are excellent maps on the site of instructors Rob and Diane McKenzie, who teach hang gliding and paragliding every day at Marshall. Find the maps here: http://www.flytandem.com/justmaps.htm
Shuttle info: http://flytandem.com/shuttle.htm
Rules
Airspace info (for XC-flights): http://www.crestlinesoaring.org/SBDairspace
WEATHER
Summer conditions mid-day are usually very strong and can be dangerous. Dust devils blow through the LZ. Pilots are encouraged to launch after 5 pm on their first flight and work earlier as they see how they like it.
Wx info: http://www.crestlinesoaring.org/weather
Webcams: http://www.crestlinesoaring.org/ptzcam