Regarding fire rings: None of the primitive camps in that part of the Park have fire rings or stoves. In fact, Fish Creek Primitive Camp is the only one of them that does have any. If you want to have a fire you will need to have it in a metal container of some sort, and pack out the ashes.
If anyone from San Diego wants to caravan, I plan to leave my house at about 0800, which should allow time to stop at the Julian Pie Company just as they open at 0900. I will pick up a couple of apple pies to go with lunch.
Also, I may have been slightly off on my estimation of distance south on S-2 from SR-78 to the Blair Valley Primitive Camp, but in any event it is just before Mile Post 23. From the meet spot we will backtrack north on S-22 a short distance to the start of the trail. Just keep an eye on the left for the Super Secret Meet Spot that Mitch was kind enough to post a picture of. There may not be a sign that actually says Blair Valley, but there is an Historical Marker sign, and a campground symbol sign. It's clearly marked on all the paper maps of the Park, and even on the AAA San Diego Region map.