>>1363089/fit/izen here.
I do distance hikes.
I would say basic workout suck as starter strength would be good. Especially since walking 15-30 miles. Gluts, quads, and hamstrings workouts are a must. Building stamina with HIIT or 10k also helps.
Nutrician is another good one. Learning to care proper macro spread helps. For me 30% protein, 50% carbs, and 20% fats keep me full and gives me enough to heal up my muscles and energy to keep going. Plus knowig which foods help deal with inflammation.
Lastly people will tell you carry 2 lbs of food. I can reduce that and focus on the calories I need instead. Reducing weight but keeping satisfied.