There are several ways to get to the Sitting Bull Rock. First drive up Summit Avenue from Mill Valley to its end, then make a left on Fern Canyon Road (which doubles as a paved section between the upper and lower sections of Old Railroad Grade Fire Road). Follow Fern Canyon up and around a long left hand loop and look for stairs at the start of the Temelpa Trail on the right before the road's next left turn upwards. Park where you can. From there the shortest way follows the Temelpa Trail 0.3 miles until it crosses the Hoo-Koo-E-Koo Fire Road. Temelpa continues unsigned straight up a narrow gulley for another 0.3 miles until an obvious clearing with a large boulder. Spend some time savoring the spirit of this protected, windless place. Read the moving words of Sitting Bull, "Tatanka Iyotaka", chief and visionary of the Hunkpapa Sioux for almost forty years.
Twenty-five yards above is an unsigned four-way junction. You can continue straight, steeply up Telephone Trail, all the way to the East Peak parking lot, or take it part way before connecting on the right with a series of newly graded switchbacks to the Temelpa Trail, which eventually exits on the Verna Dunshee paved loop encircling the summit. Or you can go diagonally to the right at the four-way junction up the steep, older gulley of the Temelpa Trail with various switchback and short-cut options along the way. As long as you keep going upwards you won't get lost.
To return from the rock, simply retrace your steps very cautiously down the gulley, or, for an easier descent turn onto the unsigned Old Plane (or Vic Haun) Trail (directly on your left at the four-way junction when facing upwards, on the right when coming down) and follow it 0.5 miles to the Hoo-Koo-E-Koo Fire Road/Old Railroad Grade Fire Road junction. From there either go left 0.4 miles on the Hoo-Koo-E-Koo Fire Road to the Temelpa Trail and turn right down its gentler lower portion back to your car, or continue down (NOT the immediate sharp right up) Old Railroad Grade for 0.7 miles, through the "Double Bow Knot", turning left at the bottom of the Bow Knot (to avoid Gravity Car Grade which heads right towards the Mountain Home), continuing down to Fern Canyon Road, with a 0.25 mile walk remaining back to your car. For a shorter alternate route than Old Railroad Grade take the unsigned Murray Trail directly across the Hoo-Koo-E-Koo Fire Road from the Old Plane/Old Railroad Grade junction, which will exit steeply onto Old Railroad Grade 0.1 mile from Fern Canyon Road, saving you almost half a mile.
For a more adventurous route to the Sitting Bull site, and also passing a secret place, park as close as you can to the upper end of Fern Canyon Road and walk 0.1 mile, past the house with the water fountain, to the first bend left on this portion of Old Railroad Grade. Follow the unsigned trail on the right of the stream bed (directly opposite the steeper, unsigned Murray Trail, which follows the left side) which will exit on the Hoo-Koo-E-Koo Fire Road. Directly across Hoo-Koo-E-Koo work your way up either side of the stream bed of Cascade Creek through an enchanting grove of thin redwood trees and look for several large pieces of sheet metal from a 1944 plane wreck that still remain. Do not attempt to remove them as they are historic artifacts. Continue up the very faint trail keeping somewhat to the right after the debris from the crash and you will shortly run into Old Plane Trail crossing from left to right. Turn right. For a short detour, about a hundred yards from this spot there is a hidden-by-brush thin trail opening that goes down to a much more extenstive site of plane wreckage, with an official plaque and enscription. At the four-way junction turn right twenty-five yards down to the Sitting Bull Rock. For more details, see Barry Spitz, Tamalpais Trails.