1) make sure everyone is wearing the shoes they’ll hike in as their everyday shoes for weeks in advance.  If their shoes are too heavy or bothersome or uncomfortable to wear to school, the store, and work, they shouldn’t hike in them, ever, and especially not when the party has some miles to do.  If you have someone along who insists on traditional, heavy ankle-high boots, insist they have been wearing them 12 hours a day for weeks in advance.  Better yet, leave that person behind.
2) do ten minutes of actual stair climbing actual stairs each morning before your shower.  Unlike a stairclimber at the gym, you’ll be raising AND LOWERING your full body weight up and down with each flight of stairs.  After a week of that, add a gallon jug of water.  Add a second jug of water the third week.  In your 30s, three weeks of such prep is more than enough.
3) 10 pound baseweights and 1.5 pounds of food per person per day.  Checked on a scale with the extra stuff left in the car.  Everything – the miles, the vertical, the long days – is easier with less weight on your back.
4) if your long days are early in your trip and high in elevation, arrive a few days early to partially acclimitize to the elevation.  Or spend the days prior at some other high elevation (e.g Mammoth or Toulemne Meadows prior to Mount Whitney).  I’ve debated if time spent in an airplane at 33,000 feet (jet keep cabin pressure around 8,000-foot density elevation) helps a bit – some months that’s most of my time above sea level.  Easy hiking at 8,000 feet is better and far less likely to develop to DVT and throw a clot.
Great suggestions, David! I have recently purchased the Topo Pursuits. I am hoping they give much more support than my Vivos and have more durability than Lone Peaks. Anyone use those yet?
I’ve been doing the stairmaster with Chase Mountain’s mountain proof knees program, but I’ll add descending stairs now as well.
My friend is obsessed with his Jetboil, so I guess I’ll let him bring it instead of my lightweight/less bulky setup. Anyone have suggestions on how to convince your hiking partners to ditch heavy or bulky gear, especially when you have something lighter? I’m not one for conflict; I usually let people hike their own hike but I know a trip like this requires more coordination and efficient packing to avoid someone getting blisters or having a bad time with a needless injury that could’ve been prevented. Maybe I’ll just have to buckle up and enforce packing light as the trip leader.
We live 2.5 hours from the trailhead and are fairly acclimated to higher elevations, but the first day is a huge elevation change (we are doing the GDT Section E).