Right off of the highway, this small forest road 705F has a bunch of small pullouts with some fire rings and parking spots for small campers and clearings for tents. AT&T has 4 bars LTE, and there are a bunch of burnable logs around. Only downside is some road noise, but very easy to access with only views of nature
Spent one night there at the spot at the very end of the gravel, pretty well maintained road. Our location was excellent, with a small pond nearby and trails. We had no one nearby. Bonus for the closeness to a rest stop (water and flush toilets) and trailhead non flush toilets. Very quiet and easy access. Not that I needed it, but I had 4 bar cell signal available.
Beautiful area. There are a lot dispersed camping sites, you just need to get there early enough. You need to find a spot with a defined access road to it and a built fire ring. Generator use is allowed. Camp fires are allowed as well as long as the wind allows it.
We found a set of campsites specifically on the forest road 705F, near the Hidden Valley picnic area. The sites are free, as they are primitive set-up with only a fire pit. Although there are not facilities immediately there, if you finding camping in this area you are close by to a bathroom at Summit Trailhead and potable water at either Hidden Valley or the Abraham Lincoln rest area. We found a whole list of forest roads that allow dispersed camping 100 feet off-road: https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprd3841999.pdf