Bechler River Trail is a strenuous point-to-point backpacking route from Bechler Ranger Station Trailhead to Lone Star Geyser. The NPS describes it as roughly 30 miles one way; the connected trail-survey line here measures about 28.7 miles and follows the Bechler River Cutoff from the ranger station into the river corridor. You go from forest and broad meadow to a waterfall-lined canyon, then toward Shoshone Lake and over Grants Pass before reaching the Firehole drainage. Allow about 20 hours of walking, generally spread over three to five days with an overnight itinerary. The remote waterfalls and thermal country reward a planned backpack; this is not a casual day walk.
The route ends at Lone Star Geyser, not at a road. The nearest vehicle access is the Lone Star Geyser Trailhead, about 2.4 miles farther along the separate trail. Arrange a shuttle between the ends and budget that extra walk if you are exiting there. Overnight hikers need a Yellowstone backcountry permit for their dates and assigned campsites; carry your own food and the equipment needed for a multi-day trip.