Grab some kettle bells or a D-Ball, about 50% of your body weight. I usually do this one in the gym or on the track to keep track of distance.
Farmer carry (racked if possible) 100m
Repeat until you have farmer carried 1 mile and ran 2 miles
Soreness Rating: Shoulders 6, legs 2
It’s pretty easy for the first half. Don’t get cocky, the pain will sneak up on you.