Begin your walk on the right branch of the Rockefeller Loop (a very pleasant family hike in its own. The full loop can only be hiked in the summer and fall. The Bull Creek loop consists of two trails: the Bull Creek Flats Trail on the south side of the creek and the Big Tree Trail on the north. At the western end the two are joined by an automobile bridge, but at their eastern end is only a seasonal footbridge that's normally installed between mid-May (but sometimes not until the end of July) and late September. At other times the creek may still be only a few inches deep and easily forded. When the footbridge is out and the creek becomes a raging torrent, the best alternative to the full loop hike is an out-and-back on the Bull Creek Flats Trail, which is the better of the two trails.