The attached topo map image of the drive in from Manzanar is a perfect guide.
When leaving 395 on the dirt road, zero out the odometer. Follow the road around the curve, past the graveyard, and past the first dirt road on the right at 1.9 mile. Continue to mile 2.5, THEN take a dirt road to the right.
The drive to the trailhead took us 35 to 40 minutes from 395 in a high-clearance 4 wheel drive.
I don't recommend low-clearance vehicles beyond the Manzanar graveyard. We took *twice as long* escorting two very low-clearance cars.
The trailhead isn't a trailhead per se. The dirt road just ends abruptly in an oak grove at George Creek. There's a parking spot (patch of bushless dirt with room for 2 vehicles) less than 100 yards from road's end, this is the 4WD parking lot. There's also the "2WD parking lot" (patch of dirt with room for 3 vehicles) about 1/2 a mile short of this.
Thank you for the description of the drive to the trail head. I've added your material to the page.
I collected some waypoints and route-finding hints on a public Google Map. Feel free to use it if it helps you plan the trip, or add your own notes for posterity.