Logistics Transportation between the endpoint trailheads is a challenge. The nearest airport is Reno, Nevada, 3.5 hours from Yosemite Valley and 4.5 hours from the Mt. Whitney trailhead. It’s a 3.5- to 4-hour drive from the Mt. Whitney Trailhead to the Valley. Unless you hire a shuttle service (below), the easiest plan for a north-south hike is to leave one vehicle at the Mt. Whitney Trailhead (crowded on weekends), leave another in Lee Vining near Yosemite’s east entrance, and take the YARTS bus (877-989-2787, yarts.com) to the Valley.
For an early start on day one, spend the night before in the Valley: Curry Village can be noisy, but it’s just a 20-minute walk from the trailhead. Otherwise, stay in either the Yosemite Lodge or Ahwahnee Lodge (559-253-5636, yosemitepark.com/accommodations.aspx); make reservations a year in advance. Valley campgrounds book up quickly; reserve a site four months in advance (800-436-7275, reservations.nps.gov/). See nps.gov/archive/yose/trip/camping.htm#campgrounds for more info. The Valley’s free buses run frequently but don’t start until 7 a.m.
High Sierra Transportation serves the Sierra and regional airports (760-258-6060, highsierratransportation.com). Check other shuttle services at climber.org/data/shuttles.html.
The only logical time for an ultralight thru-hike is mid-August to mid-September, when–usually–the mosquitoes have abated, rain is rare (allowing you to use a tarp instead of a tent), and the passes are snow-free.
Get a permit for the entire JMT from the park or forest where you plan to start, either Yosemite National Park (209-372-0740, nps.gov/archive/yose/wilderness/permits.htm), or the Inyo National Forest (760-873-2485, fs.fed.us/r5/inyo/recreation/wild/permitsres.shtml). Yosemite permits are free, but reserve one (up to 24 weeks in advance, $5/person). Yosemite has trailhead quotas for permits; if you’re day hiking from Yosemite Valley to Tuolumne Meadows (as suggested above), you can get a permit for starting the JMT at Tuolumne instead of a hard-to-get permit for the JMT/Happy Isles trailhead in Yosemite Valley.
Get the John Muir Trail map pack for $19 (the entire set weighs 3 oz.). Tom Harrison maps, (800) 265-9090 or (415) 456-7940, tomharrisonmaps.com.
John Muir Trail–The Essential Guide to Hiking America’s Most Famous Trail, by Elizabeth Wenk with Kathy Morey, incorporates the Tom Harrison maps; $18, Wilderness Press; (800) 443-7227, wildernesspress.com.