This is a VERY basic description of the first leg of one of the common XC routes from Diablo. While there are certainly some good things to learn from this description and map (and a more detailed look from GE) don’t think you now have enough info to try this route without some type of escort. There are a number of obstacles not adequately explained in this description, but it’s a good start.
First, is the beginning point – North Peak. For a glider like yours, it’s pretty important that North Peak be the launching point for XC in this direction. You will need to be at least at 5,000′ over N peak to head out toward that Trailer Par and Savior Ridge. The Trailer Park marks the beginning of fairly good landing options, and is 7 miles from N Peak.
Along this route are a number of visual references, but foremost is the Detention Facility. Certainly not a landing option, but often a thermal trigger for refueling on altitude. Don’t linger there, but be ready if a thermal pops off in this area.
Just south of the Trailer Park is Savior Ridge – a ridgeline about 1000′ high that runs parallel to Mash Creek Rd for a few miles. Savior Ridge can be a nice thermal generator, but also give you the higher ground until you get up or deck it along Marsh Creek Road.