Federal frequencies are not buried down in the county pages. When you open up the California database page look down in the lower right hand portion of the page for the "California Areawide Frequencies" heading. Scroll down to the United States Forest Service link. Once that is opened scroll down to the Sequoia National Forest. I would also suggest entering the Inyo National Forest south forest net. A large portion of the Kern Plateau is on the Inyo NF. The Olancha Peak repeater on Tone 6 (156.7) is used for the Inyo portion of the plateau.
You should also click on the Bureau of Land Management link. Program frequencies for the California Desert District and the Central California District. The California Desert District frequencies will not be heard a few miles into Tulare Co. The nearest repeater is on Government Peak, south of Ridgecrest. The nearest repeater on the Central California District is on Bear Peak, which is located north of Walker Pass on CA State Route 178. The entire length of the Sherman Pass road is on the Sequoia NF and so are the areas north, south and west of the junction of this road and the Kern River road/Great Western Divide Highway. All of the Sequoia NF portion of the Kern Plateau is on the Kern River Ranger District so the radio identifiers of people an apparatus will start with a 4. The Sequoia National Forest repeaters that cover the Kern Plateau are Sherman Peak and Olancha Peak.
Dispatch is provided by the Central California Interagency Communications Center in Porterville, which uses the designator "Porterville." This center also dispatches for the Central California District of the BLM. The BLM's Central California District is dispatched by the Federal Interagency Communications Center in San Bernardino and uses the identifier "San Bernardino."
You should also open the National Park Service link and program the backcountry net of Sequoia-Kings Canyon National Parks into your scanner. It is possible that the repeater that covers the Kern River portion of the park can be received on the Kern Plateau. A trip to the Bald Mountain lookout is worthwhile. The view of the Middle Fork of the Kern River Canyon is excellent from there as is the view of the distinctive looking Farewell Gap, located at the south rim of the Mineral King Valley. The California Desert District nets can be heard from there as well as the Angeles NF, the San Bernardino and probably a couple of repeaters on the Los Padres NF. I did not have a good handheld scanner the last time I was at this lookout so I can't tell you everything that can be heard from Bald Mountain, but given the area that can be seen from there I'm sure the listening from there would be quite interesting. Death Valley National Park and the Mojave National Preserve are also possible receptions from there. The lookout is not at that high of an elevation, but its location is just right to receive a lot of distant signals. It is possible that Joshua Tree National Park can be received from there as well.
I like the area as well, even though I haven't been there for a long time. It is out of the way and lacks any big recreation sites to draw large numbers of people. The whole area is pretty quiet in the middle of the week.
**EDIT** The Tulare County Sheriff's Department covers the area on their south net with a repeater on Sherman Peak. Inyo County has one on Government Peak. You won't hear Cal Fire and most likely will not hear the CHP, however at least the eastern portion of the plateau is in the Mojave Area Office and the nearest remote base is located on Government Peak.