Step1
Train. The good news is you won’t summit Mt. Whitney (14,497 feet) until the very end of the hike, so you’ll get acclimatized and heart-fit for it while on the John Muir Trail. But to start the hike, you do need to be able to hike 10 miles a day with a full pack on, so several weeks ahead of time, hike a couple of times a week. Aerobic exercise at the gym helps, too, but it won't build up calluses.
Step2
Break in your boots. Building up calluses on your feet is the absolute number one thing to do. Infected blisters are a common sight for hikers on the trail.
Step3
Figure out how long you’d like to spend on the trail. To do it in three weeks, you have to average about 11 miles a day. Fast packers do it in less than two weeks (they’re closer to trail runners) and even an aggressive average hiker would take two weeks. If you’ve got the time, there’s no rush, though.
Step4
Seriously consider getting a buddy. It helps immensely when it comes to food. With at least two people, you have two bear canisters. Also you’ll be splitting up the carrying of other things like a tent and stove.
Step5
Figure out where your food drops will be. Because you can’t carry all of your food for three weeks, you’ll be mailing yourself food and supply packages ahead of time. You can mail food to Tuolomne Meadows, which is about two days hike from the start of the trip. Other food drop locations include Red’s Meadows Resort, Vermilion Valley Resort at Edison Lake and Muir Trail Ranch. You can also schedule meetups along the way. Have a friend hike up Kearsarge Pass and meet you at Vidette Meadow with food.
Step7
Get a permit, available on-line through the U.S. Forest Service. Here’s good news: 40 percent of the permits are reserved for walkups. Make sure you get it stamped for exiting in the Whitney Zone, with an approximate date of your exit. Pad your estimate by a couple of days just in case you get delayed.
Step8
Figure out your car exit strategy. You can park a car at the overflow parking at Whitney Portal (at the end of the trail), but make sure you empty anything with a scent. Bears are numerous at Whitney Portal and your car must be emptied of soda cans, mints, gum, food wrappers and so on. From there, have a friend drive you up to Yosemite via Tioga Pass to begin the hike (you can spend a night in Independence, CA, along the way).
Step9
Begin hiking at Happy Isles in Yosemite (you’ll stroll down the asphalt road to get to the trail head). Enjoy the views. Take pictures. Meet your fellow hikers along the way.
Step10
Camping spots are easy to find along the Muir trail. Many are marked on the Harrison maps. Set up camp in the late afternoon while the sun is still out and it’s warm-—you don’t want to be cooking dinner and washing up when it’s cold and dark out.
Step11
Consider washing your hair and washing out laundry (hanging it outside your pack to dry) at lunch so it can dry while you hike.
Step12
Take a break at Vermilion Resort. Enjoy a few hot meals, take a shower, do laundry, make phone calls, get more fuel for your stove, pick up your food supply you mailed yourself ahead of time. You can bail out there if you want, as there is a road, but you’ll be on the west side of the mountain range.
Step13
After bagging Whitney, consider returning to your car rather than camping another night-—a hot meal can be had at the Whitney Portal store. Enjoy it and celebrate your amazing feat (and feet)!