This is the classic trailhead if you want to hike the challenging Deer Creek loop. You can park your car here and descend into the depth of the canyon. Since there is no water after you hike out from Thunder River or Deer Creek, you can cache some water or energy drinks somewhere along the "stick of the lollipop" of this loop for your hike out.
The alternate to hike down is from Indian Hollow Trailhead northeast of the Bill Hall Trailhead. From there, you will hike down the Thunder River Trail which meets the Bill Hall Trail at some point. This however will take you a lot longer, since it is the longer trail.