Maps: O42116F1, O42116F2.

T1: Little Jacks trailhead, at parking area above creek.
DOJACKT1 573338 4731074 11

D1: Viewpoint overlooking canyon.
DOJACKD1 572843 4730141 11

T3: Upper trailhead, for plateau-top goal, or if your car doesn't want to go down the horrible road to the lower trailhead.
DOJACKT3 572988 4731611 11

D3: Heavy-duty goal, on top of plateau.
DOJACKD3 570772 4729304 11

T2: Halfway Gulch trailhead, at first big gulch crossing (unless the road mentioned in the text works better).
DOJACKT2 570902 4733261 11

D2: Halfway Gulch goal: canyon narrows.
DOJACKD2 568984 4730865 11